JP5325392B2 - Airbag - Google Patents

Description

  The present invention relates to an airbag that is mounted on a vehicle and instantly inflates to protect an occupant in the event of a vehicle collision.

  An airbag device is known as a device for protecting an occupant during a collision by an automobile. This airbag device bulges and expands between the occupant and the vehicle body when receiving a certain limit of impact such as a collision, and absorbs and reduces the impact received by the occupant. The airbag device is a sensor that detects a sudden deceleration due to a collision, an inflator that generates a high-pressure gas in response to a signal from the sensor, and a high-pressure gas from the inflator inflates and deploys to mitigate the impact on the occupant. A diagnostic circuit for determining whether or not the airbag and the airbag system are functioning normally is provided.

  However, for airbags used in driver seats, passenger seats, side seats, and curtain airbag devices, the number of fabric overlaps partially with respect to the adjacent portions at locations where the fabric part terminal portions of the outer peripheral sewing portion are concentrated. Although it increases, there is a problem that a phenomenon occurs in which the sewing thread is cut when the airbag is deployed from a portion where the number of overlapping fabrics partially increases.

  As a countermeasure, it is conceivable to increase the strength by increasing the fineness of the sewing thread so that the sewing thread is not cut. However, when increasing the fineness of the sewing thread, the number of sewing needles must be increased. When the number of sewing needles increases, the needles become thicker, and it is inevitable that the needle hole becomes larger at the place where the sewing is performed. As a result, the amount of gas leak from the needle hole increases, and there is a possibility that the problem that the internal pressure of the airbag decreases will occur. Further, if the sewing thread is thickened, the material cost of the sewing thread increases and the manufacturing cost of the airbag increases.

  As a problem other than the above, there is a possibility that a problem such as skipping may occur at a portion where the overlap number of the fabrics is increased due to an increase in the number of overlaps of the fabrics in the continuous sewing portion with respect to the adjacent part. The reason for this is that sewing is usually performed by adjusting the thread tension of the sewing thread to an adjacent portion where the number of overlapping fabrics is small, so that the thread tension does not match when the portion where the number of overlapping fabrics is partially increased is sewn. It is thought that. In the case of double chain stitches that are generally used in the outer periphery sewing of an airbag, if stitch skipping occurs, there is a risk that the stitching may be frayed from the skipped portion. If the sewing is frayed, gas leaks from the airbag, and in the worst case, there is a risk that the airbag bursts (explodes).

  The present invention has been made against the background of the actual situation, and provides an airbag having uniform sewing strength as a whole, having no sewing problems such as stitch skipping, and having no locally weak portion of sewing strength. With the goal.

In the first aspect of the present invention, in an airbag formed by sewing a plurality of fabric parts, when the number of overlapping fabrics to be sewn continuously increases by 4 or more, the fabric of the fabric is continuously sewn. When the number of overlapping sheets does not increase or increases with respect to the adjacent portion, the airbag is characterized in that the increased number of sheets is three or less.

In the second aspect of the present invention, when the number of overlapping fabrics to be sewn continuously increases by 4 or more by providing a notch in the portion corresponding to the overlapping portion of the main body fabric and / or the reinforcing fabric, In the method for manufacturing an airbag, the number of overlapping fabrics is not increased with respect to the adjacent portion in the sewn portion, or when the number is increased, the increased number is 3 or less.

  According to the present invention, there is no increase in gas leak amount due to increasing the fineness of the sewing thread and an increase in manufacturing cost, and there is no problem in sewing such as stitch skipping, and the sewing strength is locally increased. An airbag without a weak portion can be provided.

  Hereinafter, the best mode for carrying out the present invention will be described with reference to the drawings.

  FIG. 1 shows an inflated and expanded state of a three-dimensional two-piece front passenger seat airbag, which is an embodiment of the airbag according to the present invention. The airbag 1 is attached to an inflator (not shown), and is provided with an attachment port 2 that is also an inflator gas injection port. The airbag 1 is formed of a main body cloth (A) 4 and a main body cloth (B) 5 that are shaped as shown in FIG. 2 so as to have a three-dimensional shape by sewing. An exhaust hole 6 is formed in the main body cloth (B) 5.

  Further, a reinforcing cloth 8 and an outer periphery sewing portion reinforcing cloth 9 are added as the cloth parts constituting the airbag 1. In the airbag 1 formed by sewing a plurality of fabric parts in this manner, the portion indicated by the fabric overlap portion a is sewn with a large number of fabric parts overlapping. Referring to FIGS. 1 and 2, in the outer peripheral sewing part 17 other than the cloth overlapping part a, the number of overlapping cloths is that of the reinforcing cloth 8 or the outer peripheral sewing part reinforcing cloth 9 in addition to the two main body cloths. There are two, a total of four. However, in the cloth overlapping part a, in addition to the four main body cloths, the four outer peripheral sewing part reinforcing cloths 9 overlap, so the total number is eight.

  Since it is necessary to improve the airtightness, the fabric overlap part a in which the number of overlapping fabrics is 8 is continuously sewn with the part in which the number of adjacent fabrics overlaps 4 pieces. Only in a, it is very difficult to readjust the thread tension. Despite the increase in the number of overlapping fabrics from 4 to 8 (the number of increase is 4), if sewing is performed with the same thread tension, problems such as stitch skipping may occur in the fabric overlap portion a. Likely to happen. Furthermore, in the fabric overlap part a, the degree of freedom of the sewing thread is lowered, the elongation of the sewing thread is suppressed and stress is concentrated, and the sewing thread is likely to be cut when the airbag is deployed. Inferred.

  Therefore, in order to reduce the difference in the number of overlapping fabrics between the fabric overlap portion a and the adjacent sewing portion, a notch 18 as shown in FIG. Thus, the increase in the number of overlapping fabrics in the fabric overlap portion a can be reduced, the stress applied to the sewing thread can be made uniform as a whole, and the sewing thread can be prevented from being cut when the airbag is deployed. The cutout 18 may be provided on either the main body cloth or the outer periphery sewn portion reinforcing cloth 9, but considering the occurrence of gas leak from the main body cloth, it is preferable to provide the notch 18 on the outer periphery sewn portion reinforcing cloth 9. The fineness of the sewing thread at this time is preferably 235 to 2,800 dtex, and more preferably 470 to 1,400 dtex. When the fineness of the sewing thread is less than 235 dtex, the strength of the sewing part may be insufficient, and when the fineness of the sewing thread exceeds 2,800 dtex, the needle hole of the sewing machine may become too large and the gas leak amount may increase. is there.

  As a material of the airbag member used in the present invention, a fiber fabric is used, for example, polyamide fibers such as nylon 6, 66, 46, aromatic polyamide fibers (aramid fibers) represented by paraphenylene terephthalamide, Polyester fibers represented by polyethylene terephthalate, wholly aromatic polyester fibers, vinylon fibers, rayon fibers, polyolefin fibers such as ultra-high molecular weight polyethylene, polyoxymethylene fibers, sulfone fibers such as paraphenylene sulfone and polysulfone, polyether ethers Ketone fiber, polyetherimide fiber, carbon fiber, polyimide fiber, and in some cases inorganic fiber (glass fiber, ceramic fiber, metal fiber, etc.) are employed, and these can be used alone or in combination. Among these, nylon 66 fiber is particularly preferable because of its excellent strength and durability.

  The fabric may be any of a woven fabric, a knitted fabric, a non-woven fabric and the like. For example, in the case of a woven fabric, there are plain weaving, satin weaving, twill weaving, Panama weaving, bag weaving, etc. There are circular knitting and the like, and in consideration of the elongation and strength of the fabric, a woven fabric is preferable, and a plain woven fabric is particularly preferable. Further, these fabrics may be coated with a resin for the purpose of improving heat resistance and reducing air permeability.

  As for the resin used for coating, for example, halogen-containing rubber such as chloroprene rubber, hyperon rubber, fluorine rubber, silicone rubber, ethylene propylene rubber, ethylene propylene terpolymer rubber, nitrile butadiene rubber, styrene butadiene rubber, Rubbers such as isobutylene isoprene rubber, urethane rubber, acrylic rubber, or halogen-containing resins such as vinyl chloride resin, vinylidene chloride resin, chlorinated polyolefin resin, fluororesin, urethane resin, acrylic resin, ester resin, amide resin, olefin resin And resins such as silicone resins, which can be used alone or in combination. Among these, a silicone resin is preferable from the viewpoints of excellent heat resistance and weather resistance and versatility.

[Example 1] Nylon 66 fiber 470 dtex Plain weave is used as the main body cloth (A) 4, the main body cloth (B) 5, and the outer periphery sewn portion reinforcing cloth 9, and the notch 18 shown in FIG. The three-dimensional two-piece passenger airbag shown in FIG. As the sewing thread, an upper thread of 1,400 dtex and a lower thread of 940 dtex were used, and the outer periphery was sewn by double ring stitching with a stitch number of 4.2 stitches / cm and a distance between stitches of 2.4 mm. There is no increase in the number of overlapping fabrics in the fabric overlap portion a. The obtained bag was checked for sewing quality, but there was no skipping defect at the cloth overlap portion a. The cloth overlapped part a was cut out to be 400 mm long and 150 mm wide, and the strength of the sewing part was measured using an autograph tester manufactured by Shimadzu. The measurement conditions were a grip width of 100 mm and a measurement speed of 200 mm / min. It is. The maximum strength was 3,598 N, the elongation was 33.2%, the energy was 41.6 J, and the strength was sufficient. Furthermore, when a bulging test was performed using a burst tester (manufactured by Ito Seiki Co., Ltd.), no gas leak occurred.

[Example 2] Nylon 66 fiber 470 dtex A plain weave is used as the main body cloth (C) 10, the main body cloth (D) 11, and the reinforcing cloth 8, and the notch 18 shown in FIG. A three-piece passenger airbag was created. In the outer circumference sewing, sewing is performed by main stitching using an upper thread of 1,400 dtex and lower thread of 840 dtex, and for bind-off sewing, an upper thread of 1,400 dtex and a lower thread of 840 dtex are used as a sewing thread and double ring stitching is performed. At the end, they sew and sew. There is no increase in the number of overlapping fabrics in the fabric overlap portion a. The obtained bag was checked for sewing quality, but there was no skipping defect at the cloth overlap portion a. The cloth overlapped part a was cut out so as to be 400 mm long and 150 mm wide, and the strength of the sewn part was measured using the Shimadzu autograph tester under the same conditions as in Example 1. The maximum strength was 3,801 N, the elongation was 32.3%, the energy was 44.3 J, and the strength was sufficient. Furthermore, when a bulging test was performed using a burst tester (manufactured by Ito Seiki Co., Ltd.), no gas leak occurred.

[Example 3] Nylon 66 fiber 470 dtex 46 plain weave, silicone resin (manufactured by Toray Dow Corning) was used as the body cloth (E) 14, the reinforcing cloth 8, and the partition cloth 16, and the notch 18 shown in FIG. A side airbag shown in FIG. As the sewing thread, an upper thread 1,400 dtex and a lower thread 840 dtex were used, and the outer periphery was sewn by double ring stitching with a stitching number of 4.2 stitches / cm and a distance between stitches of 2.4 mm. The number of overlapping fabrics in the fabric overlap portion a is an increase of 2 sheets with respect to the adjacent portion. The obtained bag was checked for sewing quality, but there was no skipping defect at the cloth overlap portion a. The cloth overlapped part a was cut out so as to be 400 mm long and 150 mm wide, and the strength of the sewn part was measured using the Shimadzu autograph tester under the same conditions as in Example 1. The maximum strength was 3,015 N, the elongation was 28.7%, and the energy was 31.2 J, and it had sufficient strength. Furthermore, when a bulging test was performed using a burst tester (manufactured by Ito Seiki Co., Ltd.), no gas leak occurred.

[Comparative Example 1] Nylon 66 fiber 470 dtex Plain weave is used as the main body cloth (A) 4, the main body cloth (B) 5, and the outer periphery sewn portion reinforcing cloth 9, without the notch 18 shown in FIG. A three-dimensional two-piece passenger airbag was created. As the sewing thread, an upper thread 1,400 dtex and a lower thread 840 dtex were used, and outer periphery sewing was performed by double ring stitching. The number of changes in the number of overlapping fabrics in the fabric overlap portion a is an increase of 4 sheets with respect to the adjacent portion. When the sewing product grade was confirmed about the obtained bag, the occurrence of a skipping defect was observed in the cloth overlapping part a. The cloth overlapped part a was cut out so as to be 400 mm long and 150 mm wide, and the strength of the sewn part was measured using the Shimadzu autograph tester under the same conditions as in Example 1. The maximum strength was 2,773 N, the elongation was 28.3%, the energy was 28.0 J, and the strength was inferior. Furthermore, when a bulging test was performed using a burst tester (manufactured by Ito Seiki Co., Ltd.), a gas leak was confirmed from the fabric overlap portion a.

  The results are shown in Table 1.

  The present invention has been described with reference to examples, but the embodiment of the present invention is not limited to this, and can be changed and improved without departing from the scope of the invention.

It is a figure which shows the bulging deployment state of the solid 2 piece passenger seat airbag of this invention. It is a figure which shows the fabric part of the solid 2 piece passenger seat airbag of this invention. It is a figure which shows the expansion | deployment deployment state of the three-dimensional three-piece passenger seat airbag of this invention. It is a figure which shows the fabric part of the three-dimensional three-piece passenger seat airbag of this invention. It is a figure which shows the bulging deployment state of the side airbag of this invention.

Explanation of symbols

1 Airbag 2 Attachment port 4 Body cloth (A)
5 Body cloth (B)
6 Exhaust hole 8 Reinforcement cloth 9 Outer circumference sewing part reinforcement cloth 10 Body cloth (C)
11 Body cloth (D)
14 Body cloth (E)
16 Bulkhead cloth 17 Peripheral sewing part 18 Notch a Cloth overlap part

Claims (2)

In an airbag formed by sewing a plurality of fabric parts, when the number of overlapping fabrics to be sewn continuously increases by 4 or more, the overlap number of fabrics in the continuous sewing portion is larger than the adjacent portion. If the air bag does not increase or increases, the increased number is 3 or less. When the number of overlapping fabrics to be sewn continuously increases by 4 or more by providing a notch in the portion corresponding to the overlapping portion of the main body fabric and / or the reinforcing fabric, the number of overlapping fabrics in the continuous sewing portion is increased. A method of manufacturing an airbag, characterized by not increasing or increasing the number of adjacent parts to 3 or less.

Images