JP2001301557A - Air bag for vehicle - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a light-weight and compact air bag having sufficient withstand pressure strength as the air bag by reducing a stitch deviation amount of a sewn part when it deploys. SOLUTION: This air bag for vehicle is manufactured by sewing a basic cloth which is a plain weave fabric made of polyamide threads having fineness of 110 to 185 dtex and tensile strength of 4.4 cN/dtex or more and bias a cover factor of 2,000 to 2,300 at a stitch interval of 2.7 mm or less using a sewing thread having fineness of 350 to 940 dtex.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to an airbag for a vehicle, and more particularly, to an airbag obtained by sewing a plain-woven base cloth.

[0002]

2. Description of the Related Art In general, an airbag is stored in a folded state in a storage portion provided in a central portion of a steering wheel of a vehicle or inside an instrument panel. It expands and expands in the room to receive the occupants.

Conventionally, such a vehicle airbag is formed by using a plain woven fabric made of synthetic fibers such as polyamide yarn as a base cloth and performing a predetermined sewing on the base cloth. Polyamide 66 yarn having a fineness of 470 dtex is generally used.

[0004]

As described above, since the airbag is disposed in a state of being folded in a vehicle, it is required that the airbag be lightweight and compact. An airbag cannot sufficiently satisfy such a demand. Therefore, it is conceivable to sew an airbag with such a low fineness cloth by using a low fineness yarn as a constituent yarn of the base cloth.

However, simply reducing the fineness lowers the mechanical strength of the base fabric, making it difficult to obtain sufficient pressure resistance as an airbag. In addition, when low-fineness cloth is used for the base cloth, if sewing is performed in the same manner as in the related art, misalignment of the sewn portion is likely to occur when the airbag is deployed. Such misregistration is caused by an increase in tension on the sewing portion due to an increase in the internal pressure of the bag during deployment of the airbag. As a result, the loss of gas for maintaining the internal pressure increases. Therefore, in an airbag, it is necessary to suppress such an amount of misalignment.

The present invention has been made in view of the above points, and has a sufficient pressure resistance as an airbag, while reducing the amount of misalignment of a sewn portion during deployment.
An object is to provide a lightweight and compact airbag.

[0007]

The vehicle airbag according to the present invention is a plain woven fabric made of polyamide yarn having a fineness of 110 to 185 dtex, and has a cover factor of 2,000 to 2,000.
The base cloth of 300 is sewn using a sewing thread having a fineness of 350 to 940 dtex with a stitch interval of 2.7 mm or less.

Here, CB = warp density × √ (fineness of warp × 0.9) + weft density ×
√ (Weft fineness × 0.9)

According to the present invention, the fineness is 110 to 185 dt.
The gas generated from the inflator is composed of a plain weave base fabric, which is made by extruding a high-density polyamide yarn of ex and a cover factor of 2,000 to 2,300 at a high density. Is excellent in internal pressure retention, and the mechanical strength of the base fabric is high even though it is a low fineness cloth, so that the pressure resistance of the airbag can be increased. In addition, since sewing is performed at a fine pitch of 2.7 mm or less using a relatively low fineness sewing thread having a fineness of 350 to 940 dtex as a sewing thread for sewing such a low fineness cloth, when the airbag is deployed. It is possible to reduce the amount of misalignment of the sewing portion due to gas generated by the inflator. As described above, a highly reliable airbag can be obtained while achieving lightweight and compact foldability.

[0010]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, matters relating to the implementation of the present invention will be described in detail.

As the single yarn constituting the vehicle airbag of the present invention, a polyamide yarn having a fineness of 110 to 185 dtex is used. If the fineness exceeds 185 dtex, it is not possible to obtain an epoch-making lightweight and compact foldability. On the other hand, if the fineness is less than 110 dtex, it is difficult to secure sufficient mechanical strength required for an airbag. From this viewpoint, the upper limit of the fineness is more preferably 176 dtex, and the lower limit of the fineness is more preferably 132 dtex.

As the polyamide yarn, polyamide 66
Yarn, polyamide 6 yarn, polyamide 46 yarn and the like. Among them, in the present invention, polyamide 66 yarn is particularly preferable.

[0013] JIS L101 of the polyamide yarn used in the present invention
3 The tensile strength (single yarn strength) according to 7.5.1 is 4.4c
It is preferably at least N / dtex. By using a polyamide yarn having such a tensile strength, the mechanical strength of the base cloth, which is a low fineness cloth, can be further increased, and sufficient pressure resistance as an airbag can be secured. Tensile strength is 5.0cN
More preferably, it is not less than / dtex. The polyamide yarn preferably has a tensile elongation of 15% or more.

The base fabric constituting the airbag for a vehicle according to the present invention is woven in a plain weave using the single yarn described above.
Its cover factor (CB) is 2,000 ~ 2,30
It is set within the range of 0. The cover factor is 2,000
If it is less than 0, the mechanical strength of the base fabric will be low, and sufficient pressure resistance as an airbag cannot be secured. On the other hand, when the cover factor exceeds 2,300, the weaving density is high and weaving becomes difficult. From such a viewpoint, the lower limit of the cover factor is more preferably 2,055, and the upper limit is more preferably 2,221. Note that the warp density and the weft density may have the same value or different values. Further, weaving of the plain woven fabric can be performed using a known loom.

Regarding the physical properties of the base fabric, JIS K6328 is used in view of securing sufficient pressure resistance as an airbag.
5.3.5 tensile strength of 250N / cm or more, tensile elongation of 2
0% or more, tear strength according to JIS K6328 5.3.6 50N
It is preferable that it is above. Further, it is preferable that the physical property retention after environmental aging is 80% or more. Here, the physical property retention after aging is determined by (C1 / C0) × 100 (%) using the physical property value C1 after accelerated aging by leaving at 110 ° C. × 500 hours at high temperature and the initial physical property value C0. .
Further, it is preferable that the air permeability by the Frazier method of JIS L1096 6.27.1.A method is 0.8 cc / cm ² / sec or less.

The base fabric constituting the airbag of the present invention is usually a non-coated fabric whose surface is not coated with a resin coating material from the viewpoint of more effectively achieving the object of the present invention. A resin coating material may be applied to both sides or one side of the cloth to form a coated cloth. In the case of a coated fabric, a silicone rubber coating material is suitable as the coating material, and it is preferable to coat the coating material on one surface of the woven fabric at a solid content of 20 g / m ² or less. By coating with such a low basis weight, an extremely thin coating film is formed such that the thickness of the base fabric after coating is substantially the same as the thickness of the woven fabric before coating, so that it is a coated cloth. The folding habit is easy to be formed, so that the compact foldability of the airbag is not impaired.

The airbag for a vehicle according to the present invention is formed into a predetermined bag shape by cutting the above-described base cloth into a predetermined shape and sewing the cut one or a plurality of cloths. .

At the time of sewing, the fineness is 350 to 940 dtex.
Sewing thread is used. If the fineness of the sewing thread is less than 350 dtex, the strength of the sewing thread is insufficient, and the pressure resistance decreases.
On the other hand, if the fineness of the sewing thread exceeds 940 dtex, the woven fabric is damaged at the time of sewing because a thick needle must be used. From this viewpoint, the lower limit of the fineness of the sewing thread is more preferably 470 dtex.

As the sewing thread, a polyamide yarn is preferably used, and more preferably, a polyamide 66 yarn is used. The sewing thread has a tensile strength (single thread strength).
Is preferably 4.8 cN / y or more, and the tensile elongation is preferably 15% or more.

The sewing is performed by using the above-described sewing thread by chain stitching or lock stitching with a stitch interval of 2.7 mm or less. If the stitch interval (sewing pitch) exceeds 2.7 mm, that is, if the number of stitches is less than 9.4 stitches per 25.4 mm, it is not possible to sufficiently reduce the amount of misalignment of the stitched portion. More preferably, the stitch interval of the sewing is 2.2 mm or less.

In the vehicle airbag of the present invention obtained as described above, the sewn portion measured according to the method B of JIS L1096 6.21.1 (seam slippage method) (however, the load is 588 N / 25.4 mm). It is preferable that the sliding resistance is 1.5 mm or less.

[0022]

EXAMPLES Next, the present invention will be described specifically with reference to examples and comparative examples, but the present invention is not limited to the following examples.

Examples 1 and 2 and Comparative Examples 1 to 3 Using polyamide 66 yarns of each fineness and tensile strength shown in Table 1, at each weaving density shown in Table 1, Examples 1, 2 and Comparative Examples 1 to A plain weave fabric No. 3 was prepared. For each of the obtained base fabrics, each physical property such as tensile strength, tensile elongation, tear strength, and air permeability was measured.

Each of the obtained base fabrics is cut to have a diameter of 76 mm.
Two circular cloths of 0 mm were obtained, and their peripheral edges were sewn to each other to produce driver airbags of Examples 1 and 2 and Comparative Examples 1 to 3. The sewing was carried out by using a polyamide 66 thread having each fineness shown in Table 1 and performing main sewing at intervals of each stitch shown in Table 1. For each obtained airbag, the mass,
The folding volume, pressure resistance, and slip resistance of the sewn portion were measured. In addition, a deployment test was performed for each airbag. Table 1 shows the results.

Each measuring method is as follows.

Tensile strength and tensile elongation: JIS K6328 5.3.5
Measure in each of the warp direction and the weft direction by
The historical values are shown.

Tear strength: Measured in each of the warp direction and the weft direction according to JIS K6328 5.3.6, and the value of the weft was shown.

Air permeability: Measured by the method A of JIS L1096 6.27.1.

Mass: The mass of each airbag was expressed as an index, with the mass of the airbag of Comparative Example 1 being 100.

Folded volume: The airbag was folded into a predetermined shape and its volume was measured. In the table, the fold volume of Comparative Example 1 was set to 100 and indicated as an index.

Pressure resistance: An air bag was filled with gas, and the internal pressure at the time of destruction was measured. In the table, the pressure resistance required for practical use is represented by an index with 100 as the index.

Sliding resistance: The amount of misalignment of the peripheral sewing portion of the airbag was measured according to the method B of JIS L1096 6.21.1 (seam sliding method) (load: 588 N / 25.4 mm).

Deployment test: The airbag was folded into a predetermined shape, housed in the pad of the driver's seat airbag, and the module with the inflator was ignited after 4 hours in an atmosphere at a temperature of 60 ° C. The airbag was deployed. Here, the inflator was a non-azide pyro-type gas generating agent having an output of 200 kPa. The output indicates the maximum pressure value measured in the 60 L tank. The evaluation criteria were "x" when the cloth or the sewing thread of the sewn portion of the bag after deployment was damaged, and "o" when there was no damage.

[0034]

[Table 1] The results are as shown in Table 1. The airbags of Examples 1 and 2 composed of the low fineness cloth were significantly lighter than the airbag of Comparative Example 1, and the folding volume was also significantly reduced. The compact folded shape was realized.
In addition, the airbags of Examples 1 and 2 had a sufficient pressure resistance, compared to the airbag of Comparative Example 2 in which the woven density of the base fabric was small. Further, the airbags of Examples 1 and 2 were smaller in the amount of misalignment of the sewn portion than the airbag of Comparative Example 3 in which the stitch interval in sewing was large.

[0035]

As described above, according to the airbag for a vehicle of the present invention, since the woven fabric made of low fineness yarn is used for the base fabric, the weight can be reduced and the thickness of the fabric can be reduced. Can be folded compactly. In addition, the base fabric has a high mechanical strength while being a low fineness fabric, so that the pressure resistance of the airbag can be increased. In addition, the specific sewing can reduce the amount of misalignment of the sewn portion when the airbag is deployed. From the above, lightweight and
A highly reliable airbag can be obtained while achieving compact foldability.

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Claims (3)

[Claims] 1. A plain woven fabric made of polyamide yarn having a fineness of 110 to 185 dtex, wherein the cover factor is 2,000.
An airbag for a vehicle, which is obtained by sewing a base cloth of ~ 2,300 using a sewing thread having a fineness of 350 to 940 dtex at a stitch interval of 2.7 mm or less. 2. The polyamide yarn having a tensile strength of 4.4 cN / d.
2. The airbag for a vehicle according to claim 1, wherein the airbag is at least tex. 3. The airbag for a vehicle according to claim 1, wherein said polyamide yarn is a polyamide 66 yarn having a fineness of 155 dtex.