JPH05301555A - Air bag - Google Patents

Abstract

PURPOSE:To reduce the possibility of a passenger being damaged by a burn and the interior of a car room being polluted by waste gas and to suit for a tendency for size and weight to be reduced by regulating exhaust of gas in an air bag and reducing the weight of the air bag itself. CONSTITUTION:An air bag consists mainly of non-woven cloth 1 wherein organic short fibers having a thermal decomposition temperature of 300 deg.C or more and heat resistance are interwined with each other through a fluid flow confounding method. Further, by regulating the degree of ventilation in a pressure of 0.2kg/cm<2> to 50-1000 cc/cm<2>/sec, an exhaust direction is regulated without forming a vent hole or by forming a vent hole 2 formed in a cylindrical shape. The non-woven cloth is used as base cloth on the side where an inflator is mounted.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an improvement of an airbag for protecting an occupant of a vehicle, particularly an automobile.

[0002]

2. Description of the Related Art In recent years, the use of air bag devices has been rapidly promoted for the purpose of protecting occupants of vehicles, especially automobiles. Conventionally, air bags of this kind have been made of synthetic fibers such as nylon 6, nylon 66 and polyester. Formed by cutting a woven fabric using synthetic rubber coated with synthetic rubber into the face contact side and the inflator mounting side, and sewing both fabrics (10) and (11) in a bag shape as shown in FIG. Has been done.

By the way, the above-mentioned conventional base cloth is coated with synthetic rubber or the like, and its air permeability is almost zero, so that the diameter of the base cloth (11) on the inflator side, which is the lower surface of the bag, is prevented in order to prevent a sudden increase in the internal pressure of the bag during a collision. 10
A structure is adopted in which at least one vent hole (vent hole) (12) of -40 mm is provided, and the reaction of the occupant by the bag is mitigated by exhausting air from the vent hole.
As shown in FIG. 4, a strap (13) is provided in the bag to control expansion.

However, even if the base cloth coated with synthetic rubber or the like has a vent hole as described above, a high temperature inflator gas is ejected from the vent hole, so that the passenger is burned and the exhaust gas contaminates the vehicle interior. Was difficult to avoid. Therefore, in order to deal with this, the surface of the woven fabric has an air permeability of ²⁰ to 16 at 0.2 kg / cm ^2.
0cc / cm ² / sec breathable elastomeric layer is formed so as to, 200 with a value obtained by converting into a bag-like structure having an inner surface area of 8000 cm ² exhaust amount at the time of 0.2 kg / cm ² pressure
An air bag of 600 l / sec has been proposed.
(JP-A-4-5144)

On the other hand, in order to reduce the weight of an air bag as a base fabric on the side where an inflator is attached, a bag body in which a heat-resistant organic film is lined on the inner surface of a synthetic fiber woven fabric or a non-woven fabric is disclosed in JP-A-2-63949. Proposed.

[0006]

However, in each of the airbags proposed above, the former is formed of an elastomer layer on a synthetic fiber woven fabric as in the conventional case, and therefore the weight is substantially the same as the weight of the conventional base cloth and is light. However, it cannot be said that the latter is suitable for weight reduction and downsizing as an airbag, and the storage space can be reduced. Problems remain in terms of preventing burn damage and vehicle interior pollution.

The present invention copes with the above-mentioned situation and eliminates the conventional vent hole by specifying the air permeability or the vent hole shape by using the non-woven fabric by the fluid flow entanglement method, or the pseudo variable vent. By controlling the exhaust direction of gas as a hall to reduce the possibility of occupant burns and the possibility of pollution in the passenger compartment due to exhaust gas, the weight of the airbag itself is reduced, and the storage space is reduced to reduce weight and size. The purpose is to adapt to.

[0008]

That is, in order to achieve the above-mentioned object, a feature of the present invention is that the organic short fibers having a thermal decomposition temperature of 300 ° C. or higher are subjected to a fluid flow entanglement method without using a binder. It is intended to basically configured the use of entangled formed comprising nonwoven fabric inflator mounting side base fabric, further adjusting the air permeability at the time of 0.2 kg / cm ² pressure to 50~1000cc / cm ² / sec It is to be used for the base fabric on the side where the inflator is attached without providing a vent hole. Further, the present invention is characterized in that a vent hole formed in a tubular shape is provided in the non-woven fabric according to the above-mentioned basic structure to regulate the exhaust direction. Further, the invention according to claim 4 of the present invention uses a core body having a projection provided at a position corresponding to the vent hole portion as a specific configuration of the cylindrical vent hole, and the fluid flow entanglement system is basically the same as the core body. The heat-resistant organic short fibers are entangled with each other so as to be formed without sewing. The invention according to claims 5 and 6 is a specific structure of an air bag in which the base cloth is sewn in a bag shape using the inflator mounting side, and the former is to adjust the sewn portion to a higher density than other portions. The latter are each characterized by having a strap inside the bag. In the present invention, however, the fibers forming the non-woven fabric are not limited to the use of fibers having a thermal decomposition temperature of 300 ° C. or higher alone, and the thermal decomposition temperature of 300 ° C.
It also includes a case where a part of the general-purpose organic fibers below is partially contained. In this case, the blending ratio of both fibers is not necessarily specified, but practically at least the thermal decomposition temperature is 300 ° C.
It is preferable to add 25% or more of the above fibers. Further, in the present invention, the fluid flow entanglement method for forming a nonwoven fabric includes not only compressed water but also an air jet method utilizing pressurized air, but most commonly, the water flow entanglement method by a high pressure jet water flow. The hydroentanglement method is a method that has recently attracted attention as one of nonwoven fabric manufacturing methods, and is a method in which a high-pressure jet water stream is applied to a short fiber web to entangle individual fibers of the web with each other. This makes it possible to obtain a thin non-woven fabric with a comparatively small basis weight without using an adhesive, has good uniformity, excellent flexibility, strength, and dimensional stability, and in particular a well-balanced strength in both the longitudinal and latitudinal directions. Can be obtained. It is an important feature of the present invention to use the non-woven fabric in which the fibers are entangled with each other by the fluid flow entanglement method and to produce the air bag using only the non-woven fabric as the base fabric.

[0009]

According to the above-mentioned constitution of the present invention, since the heat-resistant short fibers are entangled by the high-pressure jet flow, the heat resistance against the blast and flame at the time of inflator combustion when used as the base fabric for the inflator mounting side is improved. In addition, the air permeability is ensured through the woven fabric gap or the short fiber entanglement gap, and it is possible to sufficiently exhaust air without providing a vent hole with a predetermined air permeability, and to mitigate the recoil of the occupant due to the bag. it can. In this case, heat resistance is insufficient for fibers having a thermal decomposition temperature of less than 300 ° C. Moreover, since the short fibers are entangled with each other as described above, a gas filtering effect is exerted through the gaps, and it is possible to prevent burns and prevent pollution of the vehicle interior due to waste gas. Further, since the short fiber entanglement is caused by the high-pressure jet flow, an adhesive is not required and a thin layer can be formed, which contributes to weight reduction of the airbag. Further, when the tubular vent hole is provided, the gas exhaust direction is regulated to a constant value, burns can be prevented regardless of the presence of the vent hole, and the deployment efficiency is improved by folding the tubular portion during storage. In addition, by making the sewing part high density,
Further, by providing the strap, the strength of the non-woven fabric as the base fabric is reinforced.

[0010]

Embodiments of the present invention will be described below with reference to the accompanying drawings. FIG. 1 shows an example of a non-woven fabric according to the basic constitution of the present invention. (1) is a non-woven fabric composed of organic short fibers having a heat decomposition temperature of 300 ° C. or higher and having heat resistance. Here, the non-woven fabric is not limited to the use of fibers having a thermal decomposition temperature of 300 ° C. or higher alone, and may partially contain organic general-purpose fibers having a thermal decomposition temperature of less than 300 ° C., as described above. Contains at least 25% or more of organic general-purpose fibers having a thermal decomposition temperature of less than 300 ° C. Specific examples of the heat-resistant organic fiber having a thermal decomposition temperature of 300 ° C. or higher that constitutes the nonwoven fabric (1) include, for example, meta-type or para-type wholly aromatic polyamide fibers, specifically polymetaphenylene isophthalamide and polypara. Phenylene terephthalamide, copolymer of para aramid and meta aramid,
For example, it is a para-aramid copolymerized with 3,4′-diaminodiphenyl ether, and other fibers include polyparaphenylene sulfone, polyparaphenylene sulfide, polyether ether kent, and the like. These heat-resistant fibers are appropriately used. They may be used alone or as a mixture, but when high cost fibers such as aramid fibers are used, it is preferable to mix them with other fibers at 40% or less.

On the other hand, as the organic fibers having a thermal decomposition temperature of less than 300 ° C., there are commonly used fibers such as polyamide fibers such as nylon 6,66, polyester fibers, acrylic fibers, vinylon fibers, polyolefin fibers and rayon fibers.

Short fibers made of these organic fibers are usually
The average fiber length is about 3 to 8 deniers and the average fiber length is about 50 to 80 mm. The filaments can be obtained by cutting filaments, but those spun into short fibers can also be used. And, the short fiber is a fiber web layer having a basis weight of 30 to 120 g / m ² , and a high pressure jet flow is applied by a fluid flow entanglement method,
The individual short fibers are entangled with each other without the use of a binder to form a nonwoven fabric structure as shown in FIG.
At this time, the air permeability can be adjusted at any time by adjusting the basis weight of the short fiber web layer, the pressure of the high-pressure jet stream, the processing speed, etc., and by adjusting the air permeability to 0.2 kg / cm ² / sec, the inflator side base fabric can be removed from the inflator. The generated gas can be discharged from the base cloth, and vent holes are not required, so vent hole processing in the airbag manufacturing process can be omitted.

If the air permeability of the non-woven fabric is less than 50 cc / cm ² / sec at a pressure of 0.2 kg / cm ² , the air permeability will be insufficient if there is no vent hole and the bag will burst or the occupant will rebound when inflated. There is a risk of On the other hand, 100cc
If it exceeds / cm ² / sec, hot air may leak and burn the occupants. Further, when forming the non-woven fabric (1), it is also preferable to arrange the fiber density of a portion to be a sewn portion at a higher density than that of other portions at the time of sewing an air bag to increase the strength of the same portion. It is also effective to keep the strength that a strap is attached to the inside of the bag at any time as is known.
In this case, it is preferable that the strap attachment portion also has a high fiber density.

FIG. 2 shows a case in which the vent hole (2) is provided, whereas the one shown in FIG. 1 has no vent hole by adjusting the air permeability. In this case, the vent hole may be provided auxiliary to the nonwoven fabric having the predetermined air permeability, but the vent hole can be provided regardless of the air permeability. Like the known airbag, one or more vent holes (2) are tubular vent holes which are tubularly extended from the nonwoven fabric (1) as the base fabric as shown in FIG. This tubular vent hole (2) can be sewn in a tubular shape at a position corresponding to the vent hole portion by using a woven cloth, but it is not preferable because sewing requires a lot of man-hours. Using the core body (3) provided with the protrusions (3 ') as shown in the figure, attaching the core body at a position corresponding to the vent hole portion, and forming a non-woven fabric on the core body by the fluid flow entanglement method. Is desirable. As described above, when the non-woven fabric is continuously formed on the non-woven fabric (1), which is the base fabric, folding is easy, the storage space is small, and the deployment efficiency is improved. Moreover, when the high temperature gas is exhausted, the exhaust direction of the gas is regulated to be constant, which leads to prevention of burns to the occupant.

Thus, the non-woven fabric adjusted from the air permeability as described above or provided with the tubular vent hole is used as a base fabric for an air bag on the side where the inflator is attached, and is sewn into a bag shape to form an air bag. Made Since the face contacting side of the air bag comes into contact with the occupant's face when inflated, a base cloth having a relatively soft surface is used. The above-mentioned non-woven fabric is also flexible and sewn in a bag shape together with the inflator mounting side,
It can be an air bag. However, a base fabric in which organic short fibers are entangled with a synthetic fiber woven fabric by a fluid flow entanglement method,
It is also preferable to use short fibers as the surface.

Next, specific experimental examples of the present invention will be described. First, 40% of 8d, nylon 66 with a fiber length of 70 mm, 8%
d, non-woven fabric A of 50 g / m ^{2 obtained} by intertwining 3 kinds of mixed short fibers of 30% polyester having a fiber length of 80 mm, 8d and 30% of aramid fiber having a fiber length of 70 mm with a high-pressure jet water flow.
It was created. The air permeability of this nonwoven fabric A at a pressure of 0.2 kg / cm ^{2 was} 65 cc / cm ² / sec. Further, a short fiber layer was formed by using 100% of nylon 66 short fibers having 8 d and an average fiber length of 70 mm, and a high-pressure jet water stream was applied thereto to entangle the fibers to obtain a nonwoven fabric B of 80 g / m ² . The air permeability of this nonwoven fabric at a pressure of 0.2 kg / cm ^{2 was} 65 cc / cm ² / sec.

Next, for comparison, a short fiber layer made of 100% aramid fiber having the same fiber length of 8 mm and an average fiber length of 70 mm was also entangled by a high-pressure jet water flow and the air permeability at a pressure of 0.2 kg / cm ² was 30 cc / cm ^2. The nonwoven fabric C of / sec was created. Also,
Similarly, short fibers of aramid having an average fiber length of 80 mm were entangled with a high-pressure jet water stream to obtain a nonwoven fabric D having an air permeability at a pressure of 0.2 kg / cm ² of 1500 cc / cm ² / sec.
Further, similarly to the above, a high-pressure jet water stream was applied to a short fiber layer made of nylon 66 short fibers having a mean fiber length of 80 mm and having a fiber length of 5 d, and one surface thereof was coated with chloroprene rubber to prepare a nonwoven fabric E. This nonwoven fabric E had a gas permeability of 0 at a pressure of 0.2 kg / cm ² . Then, according to the following table, each of the above-mentioned non-woven fabrics was used for the face contact side and the face non-contact side (inflator mounting side) to make an airbag, and a module integrated with an inflator and an ignition device was set in a closed chamber of 50 m ^3. Then, an actual deployment test was conducted.

The results are shown in Table 1. In the table, the bag was damaged by sensory evaluation, 1 was the worst, 2 was large, 3 was partially damaged, 4 was small, and 5 was not damaged. For the air transparency, a minimum value was displayed by setting the transparency to 100% and the opacity to 0% by using a transmittance meter equipped with a tungsten lamp and a photoelectric tube 50 cm below the deployed position of the bag.
Regarding the texture, the feel and flexibility of the fabric surface were assumed to be that the airbag hits the face strongly in the event of a collision, and a hard texture was defined as 1 and a soft texture was defined as 5 for sensory evaluation. Margin below

[0019]

[Table 1]

From Table 1 above, it can be seen that Examples 1, 2, and 3 relating to the airbag of the present invention show good results. Especially for normal air bag performance, most of the damage to the bag is due to high air pressure and poor heat resistance, so 4 or more is required, air transparency is 60 or more, texture is from scratching side. Softer is said to be more preferable, but the one according to the present invention is good in all of them as seen from Table 1 above.

[0021]

As described above, the present invention forms the air bag inflator mounting side only with a non-woven fabric in which heat-resistant short fibers are entangled by a high-pressure jet flow by the fluid flow entanglement method. Because of its breathability, it is possible to exhaust air from the cloth without providing the vent holes that were conventionally provided on the inflator mounting side base cloth, and especially for the instantaneous protection of the occupant in the event of a vehicle collision and the subsequent exhaust conditions. By appropriately adjusting and, it is possible to more reliably mitigate the recoil of the occupant caused by the air bag. Moreover, since the non-woven fabric in the present invention is entangled with heat-resistant fibers, it does not melt even by the gas generated from the inflator, and has the role of a waste gas filter in combination with the absence of vent holes. Prevent the pollution of the vehicle interior due to waste gas. In addition, since there is no vent hole and air can be exhausted from the cloth, sudden blasts and fires can be prevented from venting from the vent hole, preventing burns to the occupants and ensuring safety. There is also an advantage that the vent hole processing process can be omitted and the process can be rationalized.

Furthermore, since the whole is a non-woven fabric, it is softer than a woven fabric, and does not scratch or scratch the face due to sudden expansion. In the non-woven fabric of the present invention, the sewn portion is made to have a high density, and a strap is provided in the bag to further strengthen the sewn portion. In addition, when providing the vent hole, it is possible to improve the deployment efficiency by folding the vent hole into a tubular shape when it is stored, and the exhaust direction of the gas becomes constant during high temperature gas exhaust,
It has the effect of preventing burns.

[Brief description of drawings]

FIG. 1 is a partially enlarged sectional view of a woven fabric according to an essential part of the present invention.

FIG. 2 is a partially enlarged cross-sectional view of a nonwoven fabric according to the present invention provided with a tubular vent hole, wherein the left vent hole shows a state of making and the right side shows an inward folding state.

FIG. 3 is an external view showing an outline of an airbag.

FIG. 4 is a cross-sectional view showing the internal structure of the airbag.

[Explanation of symbols]

 (1) Non-woven fabric (2) Vent hole (3) Core

Front Page Continuation (72) Inventor Kotaro Isaji 100 Fujinoki, Tianjin, Itami City, Hyogo Prefecture Toyo Tire & Rubber Co., Ltd. Tire Technology Center (72) Inventor Toru Ozaki 3 Ichigayama, Uchikuji, Nishikamo-gun, Aichi Prefecture Toyo Tire & Rubber Co., Ltd. Automotive Parts Technology Center

Claims (6)

[Claims] 1. In a bag-shaped sewn air bag, the base fabric used on the side where the inflator is mounted is made of organic short fibers having heat resistance at a thermal decomposition temperature of 300 ° C. or higher, without using a binder, by fluid flow entanglement. An air bag characterized by being a non-woven fabric formed by entanglement by a method. 2. In a bag-shaped sewn air bag, the base fabric used on the side where the inflator is mounted is a fluid entanglement of organic short fibers having heat resistance at a thermal decomposition temperature of 300 ° C. or higher without using a binder. The entanglement is formed by the method, and the air permeability at a pressure of 0.2 kg / cm ^{2 is} 50 to 10
An air bag characterized by being a non-woven fabric adjusted to 00 cc / cm ² / sec, the non-woven fabric having no vent holes. 3. An air bag sewn in a bag shape, wherein the base cloth used on the side where the inflator is attached is a fluid flow entangled organic short fiber having a heat decomposition temperature of 300 ° C. or higher without using a binder. An air bag, which is a non-woven fabric formed by entanglement by a method, in which a vent hole provided in the non-woven fabric is formed to extend in a tubular shape. 4. A core body having a protrusion provided at a position corresponding to a cylindrical vent hole is used, and a heat-resistant organic short fiber is entangled with the core body by a fluid flow entanglement method to thereby form a cylinder without sewing. The air bag according to claim 3, wherein the air vent is provided. 5. The sewn portion of the non-woven fabric entangled by the fluid flow entanglement method is adjusted to a high density.
The airbag according to any one of 1. 6. The airbag according to claim 1, wherein the airbag sewn in a bag shape has a strap inside the bag.