JP2001097156A - Air bag for side part - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an air bag for side parts, which is lightweight and excellent in air-tightness and which can be compactly housed. SOLUTION: The air bag for side parts, which is formed into a bag by lapping two main foundation cloths covered with thermoplastic resin of the melting point of 150 deg.C or more, is a cloth in which yarns with the denier of 210 or less are used and the Metuke (weight/unit area) of which is 150 g/m2 or less. At the overlapped part at which the main foundation cloths are lapped one over the other, preferably at the outer peripheral joined part, one foundation cloth is lapped on the other foundation cloth to be joined to each other by thermal welding.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention
BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an airbag for protecting an occupant, and more particularly to a side airbag that is light and compact, can be stored compactly, and has excellent airtightness.

[0002]

2. Description of the Related Art In recent years, airbag systems have become widespread as occupant protection safety devices, and the number of mounting parts has been increasing from driver seats to passenger seats, side collision protection, and rear seats.

[0003] In particular, an airbag that protects an occupant from the impact of a side collision, that is, a side collision protection airbag (hereinafter, referred to as an airbag).
(Referred to as side airbags) has been attracting attention as a means for further enhancing safety for occupants.

However, since the side airbag is deployed in a narrow space between the occupant seat and the vehicle body, it is necessary to protect the occupant with a small-sized or small-sized bag. Unable to absorb energy enough,
Consideration must also be given to avoiding problems such as contact with the occupant and impact.

In particular, in order to prevent the occupant from violently hitting or damaging the side window or the vicinity thereof by the impact of the side collision, the occupant is deployed along the side window and covers all or a part of the window. The side bag, i.e., the inflatable curtain, has a high airtightness that prevents gas from leaking from the bag for a long time after deployment so that the head of the occupant is protected even if the vehicle rolls over due to a side impact. Is required.

In addition, in an inflatable curtain housed in a vehicle body around a side window, since a storage portion such as a pillar portion and a roof side rail portion is extremely narrow, it is necessary to reduce the volume and cross-sectional area of a folded bag. Yes, when using the base cloth used for conventional driver's and passenger's seat bags, it is necessary to take measures such as changing the design of part of the body structure and installing a separate storage unit to accommodate the folded bag. there were. For example, JP-A-10-12938
No. 0 proposes a method for improving the airtightness by solely or in combination of sewing, covering with a sealing material, covering with a coating, adhesion, heat welding, and the like, with respect to a method of joining an outer peripheral portion of a side airbag. However, while the outer peripheral portion is extremely robust and high airtightness can be obtained, it tends to be coarse and hard, and it is difficult to reduce the folding volume.

Further, Japanese Patent Application Laid-Open No. 10-109607 discloses a technique in which a bag body is formed by bag weaving and the entire bag portion is sealed with a non-permeable coating material. Airbags made by sack weaving are joined at the stage of weaving, so sewing in the post-process can be omitted, but it is necessary to coat both the front and back sides of the woven fabric, and the woven portion is still coarse. It may be hard and cannot be stored compactly.

On the other hand, an extremely thin woven fabric is made using fine denier yarn, and the airbag is compactly folded,
There have been proposals to reduce the storage space.

For example, US Pat.
An airbag using a woven fabric using nylon 66 from 5 denier to 140 denier is described. The basis weight of these fabrics is half or less than that of a conventional airbag fabric, and exceeds the conventional level in terms of weight reduction. However, since the mechanical properties of the woven fabric itself are insufficient compared with the conventional woven fabric for airbags, the airbag of the above invention has a rectangular outer peripheral shape, and attempts to secure pressure resistance of the bag body by eliminating sewing at the outer peripheral portion. Is what you do.

[0010]

However, this proposal cannot be applied to a bag having a complicated shape such as a side airbag. In addition, if a small-denier woven fabric is applied to the bag using fine denier, it can contribute to weight reduction and compactness.However, in order to secure the reliability of the airbag as a safety device, at the same time, strength and It must also be airtight.

The present invention provides a lightweight side airbag which is required for an inflatable curtain, particularly for an inflatable curtain, while maintaining a high airtightness and at the same time having an extremely excellent compact storage capacity. is there.

[0012]

SUMMARY OF THE INVENTION The present invention is directed to a side airbag, particularly a lightweight side airbag suitable for inflatable curtains, which can be stored extremely compactly while maintaining high airtightness. As a result of diligently devising the manufacturing technology, the above-mentioned problem could be solved.

That is, according to the present invention, (1) the melting point is 150
A side protection airbag formed by laminating two body base cloths each having at least one surface coated with a thermoplastic resin having a temperature of at least one degree Celsius or higher, and having a body base cloth having a denier of 210 denier or less. A side airbag, which is a woven fabric using yarn and having a basis weight of 150 g / m ² or less, wherein at least a part of an overlapping portion of the main body base fabrics is joined by heat welding; 2) The two main base fabrics are cut into substantially similar shapes, and the covering surfaces of the thermoplastic resins of the respective base fabrics are overlapped with each other. The side airbag according to (1), wherein one of the large-sized base fabrics is joined to the other small-sized base fabric by heat welding in a state where the base fabric is folded on the other base fabric. (3) At least the overlapping portion of the two main body base fabrics The side airbag according to the above (1) or (2), wherein the portions are joined by heat welding and sewing, and (4) at least a part of a joining portion between the two main body base fabrics. Are joined by thermal welding while sandwiching the thermoplastic resin alone or a reinforcing cloth laminated with the thermoplastic resin. 3. The side according to (1), (2) or (3), Part airbag.

The side airbag according to the present invention has a melting point of at least one side of at least one side of the main body base fabric in order to reduce gas leakage from a joint portion between the two main body base fabrics constituting the bag body.
It is important that a thermoplastic resin having a temperature of 180 ° C. or higher, preferably 180 ° C. or higher, is laminated, so that heat welding between the main base cloths can be performed. Gas leakage can be minimized.
If the melting point of the thermoplastic resin is lower than 150 ° C., it may not be possible to secure sufficient shielding properties against hot gas from the inflator.

In the present invention, the weight of the airbag is reduced,
Denier is 210 denier or less for compactness, while 70 denier or more, preferably 100 to 200 denier basis weight using a raw yarn of 150 g / m ² or less for securing necessary strength, strength and 80 g / m ² or more, preferably 100 to 1 to ensure airtightness
A woven fabric of 50 g / m ² is used. In this case, it is possible to provide a side airbag that is extremely light and can be stored compactly.

If the denier of the main body fabric exceeds 210 d, it is difficult to greatly reduce the storage space for the airbag. Further, when the basis weight exceeds 150 g / m ² , it is difficult to obtain a lightweight airbag.

Further, in the present invention, the two base fabrics are cut into substantially similar shapes, and the thermoplastic resin coating surfaces of the respective base fabrics are overlapped with each other. By bonding one of the base fabrics, which is the larger one of the base fabrics, on the other one of the smaller base fabrics by heat welding, a high airtightness of the outer peripheral joint is ensured. (See FIG. 7).

It is preferable that the two base fabrics are cut so as to have substantially similar shapes, but a straight portion or a gentle curved portion may be provided with a difference which can fold one of the base fabrics. The two main fabrics may be cut into similar shapes so that the folded width of one fabric is 10 to 50 mm, preferably 20 to 40 mm. The welding width of these folded portions and the like may be performed according to the obtained welding strength,
Usually, it may be performed at 20 to 30 mm.

In the present invention, particularly for a portion requiring strength, sewing may be performed after or before welding to reinforce the welded joint. However, joining by welding contributes to more compactness than joining by sewing. Therefore, it is better to minimize this combination. This is because the sewn portions overlap and become coarse and hard when folded.

In order to increase the joining strength of the joints to be thermally welded, the joints may be thermally welded with a thermoplastic resin film or sheet or a reinforcing cloth laminated with the thermoplastic resin interposed therebetween. .

The thickness of the thermoplastic resin sandwiched between the joints may be determined according to the resin layer laminated on the main body base fabric.
For example, in the case of a film or a sheet, 50 to 500 μm
And it is sufficient.

The thermoplastic resin used in the present invention has a melting point of 15
It is essential that the temperature is 0 ° C. or higher, but at the same time, it is desirable to have excellent properties such as weldability, non-adhesion at high temperature, adhesion to the base fabric, and flexibility at low temperature. However, it suffices if it can be used as a gas shielding layer of an airbag,
For example, nylon 610, 612, 6/66, 6/66
/ 12, 6/66/610, etc., polyamide resin, aliphatic or aromatic / aliphatic copolymerized polyester resin, polyether type, polyester type or polycarbonate type polyurethane resin, polyvinyl alkyl ether resin, polyhalogen One or two or more of vinyl chloride resins or various modified resins thereof may be used, and silicone-modified or fluorine-modified polycarbonate-type polyurethane resins are particularly preferable.

The lamination of the thermoplastic resin on the base fabric may be performed by any method as long as it is excellent in adhesion and welding properties between the resin and the base fabric. Any processing method such as a laminating method, a powder coating method, and a dipping method may be used. The amount of the thermoplastic resin to be laminated on the base fabric may be determined according to the required airtightness, weldability, heat resistance, etc., for example, 10 to 50 g / m ² in a coating method such as coating. In the method or the like, the thickness may be set to 10 to 80 μm.

Further, in order to improve the adhesion between the thermoplastic resin and the base fabric, a primer treatment or the like may be used on the base fabric side or the film side to be laminated.

These thermoplastic resins may contain various additives usually used for improving processability, weldability, surface properties or durability, such as a crosslinking agent, a reaction accelerator, a reaction delay, and the like. Agents, heat stabilizers, antioxidants, light stabilizers, antioxidants, lubricants, leveling agents, pigments, water-repellent agents, oil-repellent agents, concealing agents such as titanium oxide, gloss-enhancing agents,
One or more of a flame retardant, a plasticizer, and the like may be used.

The fabric constituting the airbag of the present invention is not particularly limited as long as it has excellent mechanical properties, heat resistance, adhesion to the shielding layer, and the like required for the airbag. The fiber yarns constituting the woven fabric are not particularly limited. For example, nylon fibers such as nylon 6, nylon 66, nylon 46, nylon 610, or the like, or polyamide fibers or polyethylene obtained by copolymerization or mixing thereof are used. Terephthalate, polybutylene terephthalate, such as polyethylene naphthalate alone or copolymerized thereof, polyester fiber obtained by mixing, paraphenylene terephthalamide, and aramid fiber represented by a copolymer thereof with an aromatic ether, Polyaromatic fiber such as wholly aromatic polyester fiber, vinylon fiber, ultra high molecular weight polyethylene, vinyl chloride and vinylidene chloride fiber, fluorine fiber including polytetrafluoroethylene fiber, polysulfone fiber, polyphenylene sulfide fiber Wei (PPS), polyether ether ketone (P
EEK) fiber, polyimide fiber, polyetherimide fiber, cellulosic fiber including high-strength rayon, acrylic fiber, carbon fiber, glass fiber, silicone carbide (SiC) fiber, alumina fiber, etc. In some cases, inorganic fibers such as metal fibers represented by steel may be included.

Various additives usually used for improving the preventive properties, processability, and durability of the materials are used in these fiber yarns, such as heat stabilizers, antioxidants, light stabilizers, and antioxidants. One or more of a lubricant, a smoothing agent, a pigment, a water-repellent agent, a water-repellent agent, a hiding agent such as titanium oxide, a gloss-imparting agent, a flame retardant, a plasticizer, and the like may be used. Further, depending on the case, processing such as twisting, bulking, crimping, and winding may be performed.

Further, the yarn is not particularly limited, such as filaments of long fibers, spun yarns of short fibers, and composite yarns thereof.

In the present invention, at least a part of the overlapping portions of the main body base fabrics is joined by heat welding, but the joining method is not particularly limited, and a contact or non-contact type external heating, high frequency, It may be selected from methods usually used for welding, such as a sound wave and a laser, and may be any of a continuous type, a batch type, and the like.

Further, in the present invention, in particular, a portion where the joining strength needs to be increased may be sewn in addition to joining by heat welding. In the case of sewing after joining by heat welding, or in the case of joining by heat welding after sewing, the sewing may be any as long as it can reinforce the joint, but the denier of the thread constituting the main body base cloth is In consideration of the thinness, it is preferable that the sewing is performed under the conditions that the thread count T and the number of needles S (needle / cm) to be used satisfy the relationship of 20 ≦ T ≦ 80 and 2 ≦ T / S ≦ 8.

The stitch specifications according to the present invention may be selected according to the fabric used, the specifications of the bag, the required joint strength, and the like. For example, lockstitching, double chain stitching, one-sided stitching, There are overlock sewing, safety sewing, zigzag sewing, flat sewing and the like, and a combination of these may be used.

In the present invention, the sewing thread used is an upper thread,
When the thread count is different for the lower thread and the like, it is desirable that all the sewing threads satisfy the relational expression of the present invention and the relation of the expression. Should be satisfied. The sewing thread used in the present invention 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, polyester, vinylon, aramid, carbon, glass And any of a spun yarn, a filament plied yarn and a filament resin processed yarn.

The airbag according to the present invention is a side airbag for protecting the vehicle from side impacts, and in particular, inside the vehicle body (front pillar, roof side rail, center pillar, etc.) around the side window. , Rear pillars, etc.) and stored in a folded state, near the side windows by the gas ejected from the inflator at the time of a side collision where a high load acts on the airbag bag body (the space under the roof side seal in the vehicle interior, the front pillar, It is a side collision protection airbag that is deployed in a curtain shape from the center pillar or the rear pillar to the space below the roof side rail) and can be applied to, for example, the airbag arrangement structure described in Japanese Patent Application Laid-Open No. H10-138861.

A bag that is deployed near the side window and along the window in some cases has a thin and wide shape in many cases. Therefore, the connecting portion (attaching portion) may be provided at a plurality of locations. . The connecting portion is provided at the outer edge of the outer peripheral welding portion 3 in FIG. 1, but the connecting interval may be different depending on the connecting portion. The shape of the airbag may be selected from the shape of the side window such as a cylinder, a triangle, a square, a trapezoid, an ellipse, and a curtain, an area to be protected, a storage area, and the like.

The reinforcing cloth used to reinforce the periphery of the inflator mounting opening or the outer peripheral joint of the airbag according to the present invention may be the same fabric as that used for the bag body. 840 of nylon 66
A single fabric or a plurality of fabrics thicker than the fabric for the airbag of the present invention, which is made using denier, 420 denier, or 315 denier, may be used. The reinforcing cloth referred to here includes a flameproof cloth for blocking hot gas ejected from the inflator, and in order to impart heat resistance to the reinforcing cloth, a heat-resistant resin such as a silicone resin, a fluororesin, or a heat-resistant rubber is used. Or the like, or a cloth using heat-resistant fiber such as aramid fiber may be used.

The airbag of the present invention is directed to a side airbag for side collision protection, but may be functionally applied in some cases, such as a headbag for rear-end collision protection, a mini bag for infant protection, and a bag for seat belt. It can be applied to any part that can be used, and the shape, capacity, and the like may satisfy the required requirements.

[0037]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described more specifically below with reference to examples. In the examples, the performance evaluation of the airbag was performed by the following method.

(1) Airtightness The inflator insertion portion of the bag is partially sewn, and pressurized air is injected into the bag in a sealed state except for the pressurized air supply portion, and after the bag internal pressure reaches 50 kpa, pressure is applied. The supply of the compressed air was stopped, and the time required for the internal pressure of the bag to become 0 kpa was measured by a pressure gauge provided near the pressure supply valve.

(2) Folded Thickness The thickness of the bag was measured in a state where the bag was folded in an accordion shape 10 times in parallel with the longitudinal direction, and the thickness was measured. Value.

Example 1 Nylon 66 fiber 140d / 68f (raw yarn strength 8.2 g)
/ D) was woven into a plain woven fabric having a weaving density of 92 / inch in both warp and weft. This fabric is scoured and heat-set, and then a polycarbonate-type polyurethane resin (1,6 hexanediol, a reaction product of a polycarbonate-type diol obtained from the reaction of diethylene glycol and ethylene carbonate with isophorone diisocyanate) is applied to one side of the fabric. The melting point of the emulsion and resin is 18
(5 ° C.) 20 g / m ² (in terms of solid content) was applied, dried and heat-treated to obtain a coated base fabric. The density of the woven fabric after coating was 95 yarns / inch and 93 wefts / inch, and the basis weight of the woven fabric was 126 g / m ² before coating and 146 g / m ² after coating.

Next, two coating base fabrics 1 and 2 were cut into a substantially parallelogram shape as shown in FIG. 1 as a main body member of the airbag. At this time, the length of each side was 160 cm for the upper side, 180 cm for the lower side, 80 cm and 65 cm for the hypotenuse, and the height was about 55 cm. The coating surfaces of the two cutting cloths 1 and 2 are superimposed on each other, and the outer peripheral portion 3 and the bag main body portion are formed at a welding width of 20 mm at four places (4a to 4d in FIG. 1) using a high frequency sewing machine (manufactured by Quinlite Electronics Seiko) Was welded to the outer shape of the “eyebrows”. "Mayu-shaped" shape is about 30c in height
m, about 15 cm in width.

Next, pressurized air was injected while a rubber tube was inserted through the inflator mounting port 10 and sealed. FIG.
Shows a cross section taken along the line AA in FIG. When the internal pressure of the bag reached 50 kpa, the pressurization was stopped, and the time until the internal pressure of the bag became 0 kpa was measured.

The thickness of the bag folded in an accordion shape parallel to the upper and lower sides of the main body member was measured. Table 1
As shown in the figure, a conventional product created by sewing (Comparative Example 2)
It was more airtight than the one described above, and could be stored extremely compactly.

Example 2 In Example 1, of the two cut cloths 1 and 2, 2 was set to 1
Example 1 was cut out as a similar shape (increased by 40 mm outside of 1), and the outer peripheral portion was folded on 1 and welded and joined as shown in FIG.

Airtightness and folded thickness were measured in the same manner as in Example 1. The airtightness is further improved than in Example 1, and the folded thickness is slightly thicker than in Example 1. However, compared to the conventional product (Comparative Example 1), it can be stored sufficiently compact.

Comparative Example 1 In Example 1, nylon 66 fiber 315d / 72f (raw yarn strength 9.5 g / d) was used as the main body member of the airbag.
The same procedure as in Example 1 was carried out, except that a plain fabric having a weaving density of 62 / inch in both warp and weft and a coating base fabric of 30 g / m ² was used.

[0047] The fabrics used mass per unit area, is before coating 193g / m ^2, after the coating was 223g / m ^2. The airtightness and the folded thickness were measured. It was found that the airtightness was excellent, but the folded thickness was large and the compact storage was inferior.

Comparative Example 2 An airbag was prepared in the same manner as in Comparative Example 1 except that an addition-type thermosetting silicone resin was used as a coating agent, and the characteristics were evaluated.

Here, the outer peripheral joint and the joint 4 inside the bag body
At the point, using sewing thread made of nylon 66 fiber (both upper thread and lower thread are both 8th thread), the number of stitches is 3.5 stitches / cm, the outer circumference is double chain stitch (two rows), and the inside of the bag is final Sewing at
A moisture-curable silicone resin was applied to the top of all stitches and the outside of the seam allowance at the outer peripheral portion, and sealing was performed. As shown in Table 1, the obtained airbag was low in airtightness, large in folded thickness, and inferior in compact storage.

[0050]

[Table 1]

[0051]

As described above, according to the present invention, it is possible to store it lightly and compactly, and to have the necessary strength.
A highly reliable side airbag with excellent airtightness can be obtained.

[Brief description of the drawings]

FIG. 1 is an explanatory view of an airbag of the present invention before deployment as viewed from a side window.

FIG. 2 is a sectional view taken along line AA of FIG. 1 after development. The outer peripheral portion 3 and the thick line portions 4a to 4d are welded.

FIG. 3 is an explanatory view of another embodiment of the present invention before deployment as viewed from a side window.

FIG. 4 is a sectional view taken along line AA of FIG. 3 after development.

FIG. 5 is an explanatory view of a welded outer peripheral joint portion of the airbag of the present invention.

FIG. 6 is an explanatory view of another embodiment of the welded outer peripheral joint portion of the present invention.

FIG. 7 is an explanatory view of still another embodiment of the present invention.

FIG. 8 is an explanatory view of still another embodiment of the present invention.

[Explanation of symbols]

1, 2 and 11, 12 Airbag body base cloth 3 and 13 Peripheral joints of airbag body base cloths 4a-4d and 14a-14d Joints of body base cloths 5a-5e and 15a-15e Inflated parts of airbag 6 and 7 thermoplastic resin laminated on main body base cloth 8 thermoplastic resin sandwiched between welded portions or reinforcing cloth laminated with thermoplastic resin 9 sewing thread 10 inflator mounting opening

Claims (4)

[Claims] 1. An airbag for protecting a side portion, comprising two body base cloths each having at least one surface coated with a thermoplastic resin having a melting point of 150 ° C. or higher, and formed into a bag-like shape. Is a woven fabric having a basis weight of 150 g / m ² or less, using a yarn having a denier of 210 denier or less, wherein at least a part of an overlapping portion of the body base fabrics is joined by heat welding. Side airbag. 2. The two body base cloths are cut into substantially similar shapes, and the thermoplastic resin covering surfaces of the respective base cloths are overlapped with each other. 2. The side air according to claim 1, wherein one of the large-sized base cloths is joined to the other small-sized base cloth by heat welding in a state of being folded over the other base cloth. bag. 3. The side airbag according to claim 1, wherein at least a part of the overlapping portion of the two main body base fabrics is joined by heat welding and sewing. 4. At least a part of a joining portion between the two main body base fabrics is joined by heat welding while sandwiching the thermoplastic resin alone or a reinforcing cloth laminated with the thermoplastic resin. The side airbag according to claim 1, 2 or 3, wherein: