JPH03248947A - Air bag - Google Patents

Abstract

PURPOSE:To reliably prevent forward movement of a waist and legs and to improve storing by setting the thickness of the portion, positioned facing the waist and the legs of a passenger, of an air bag to a relatively low value when an air bag formed of a tape wound in a bagform manner is expanded for development. CONSTITUTION:In manufacture of an air bag, after a tapeform opening thread 1 is first impregnated with a given rubber solution 3 through the passage of it through a rubber solution impregnating device 2, an adhering amount is controlled by means of a doctor knife 4 to provide a very thin tape 5 coated with the rubber solution 3. The tape 5 is caused to pass between rollers 7 and 8 positioned facing each other and passes through a pair of rollers 9 and 10. Thereafter, the tape is wound around a disc-shaped mandrel 13, precoated with a mould release agent, through a delivery eye 11 reciprocatively moved in a direction paralleling a rotary shaft 12 of the disc-shaped mandrel 13. The tape 5 is wound in a state that when the air bag is expanded for development, the thickness of a portion positioned facing the waste and the legs of a passenger is decreased, and the thickness of other portion is increased.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention is usually housed in the center of the steering wheel of a vehicle, and detects the impact when the vehicle collides or suddenly stops to avoid a collision. This invention relates to an airbag that instantaneously inflates and deploys to ensure the safety of drivers, etc.

[Conventional technology]

This airbag protects the occupant by being inflated with gas and deployed between the occupant and the vehicle body, and generally has the configuration shown in FIG. 5.

(hereinafter referred to as prior art ■) No. 5 showing this prior art ■
In the figure, gas ejected from an inflation flake (not shown) in the steering wheel 15 first hits the center of the upper base 21A of the airbag 21, and then flows upward and downward, as shown by arrows. Therefore, since the airbag 21 inflates from the portion facing the upper body of the occupant 16, the airbag 21 is inflated from the portion facing the upper body of the occupant 16, so regardless of the occupant's 16 seating position, the airbag 21
It was not possible to sufficiently prevent No. 6's waist and lower legs from moving toward the front of the vehicle (to the left in the diagram). (The state after movement of the occupant is shown by a solid line, and the state before movement is shown by a two-dot chain line.) Therefore, in order to solve the problems of Prior Art I, the following idea has been disclosed.

Utility Model Application Publication No. 1-150156 discloses an air bag body (
A partition body 32 is disposed inside the airbag (corresponding to the airbag of the present application) 31 to guide the gas flow so that the airbag body inflates downward and then expands upward. A patented lug bag body design (hereinafter referred to as prior art (2)) is disclosed (see FIG. 6, arrows indicate gas flow).

Furthermore, in Japanese Utility Model Application Publication No. 1-150157, a sub-airbag bag body is connected to the lower part of the main airbag bag body, and the sub-airbag bag body is configured to deploy toward the knees or thighs of the occupant. A device (hereinafter referred to as prior art (2)) regarding an airbag body characterized by the following has been disclosed.

Furthermore, Japanese Utility Model Application Publication No. 1-123756 discloses an airbag that is built into a steering wheel and deploys by introducing gas to restrain the driver, and an airbag that is auxiliary to the vehicle body when the airbag is deployed. A device related to an airbag device characterized by having an airbag support member that supports and restricts the movement of the airbag (hereinafter referred to as prior art
) has been disclosed.

[Problem to be solved by the invention]

However, since the conventional techniques (1) to (4) have a partition body, a sub-airbag body, or a supporting member, the structure inside and around the airbag is complicated, and the operational reliability thereof is not necessarily perfect. Further, since the conventional techniques (1) to (4) have many attached members, the airbags are bulky and have problems in terms of storage.

The present invention has been made in view of these problems of the conventional technology, and its purpose is to effectively prevent the hips and lower limbs from moving forward in the vehicle regardless of the seating position of the occupant. Our objective is to provide an airbag with excellent storage properties.

[Means to solve the problem]

In order to achieve the above object, the gist of the present invention is to provide an airbag in which fiber filaments are arranged in a substantially linear and parallel state or in which the tape is wound into a bag shape. The airbag is characterized in that when the bag is inflated and deployed, the thickness of the part facing the waist and lower legs of the occupant is thinner than the other parts.

In the present specification, the term "tape-like material" refers to a material in which 11 or several yarns (multifilament threads) are arranged in a sheet-like manner so that the monofilaments are maintained in a substantially straight and parallel state. , "tape" means "
"The monofilaments that make up the above tape-like material are interconnected and integrated."

The fibers of the present invention typically include human silk, polyvinyl alcohol fibers, aliphatic and aromatic polyamide fibers,
Examples include polyester fibers, carbon fibers, glass fibers, etc., but they are not particularly limited, and include all fibers conventionally used for bonding with rubber.

There is no particular restriction on the fineness of the above yarn, but it is generally 3.
A range of 0 to 30,000 D is suitable. of course,
These do not necessarily need to be supplied as a single thread; rather, it is easier to spread laterally if a plurality of threads are supplied at the same time. The thinner the monofilament fineness is, the easier it is to spread, and the preferable range is, for example, 0.8 to IOD.

Methods for opening these yarns include electrical methods, mechanical methods, and methods using air flow, but any method may be used as long as the purpose can be achieved.
Any method such as that disclosed in Japanese Patent No. 3-69626 may be used.

Note that the tape-like material obtained by the opening must be extremely uniform (with little variation in thickness). In addition, the monofilaments must be completely separated from each other, and their spacing must be close enough that the average spacing is less than the average filament diameter.

As a method for obtaining a "tape" from a "tape-like object", for example, the "tape-like object" may be coated with an elastomer.

The elastomer preferably has flexibility and appropriate elasticity. For example, natural rubber or synthetic rubber such as acrylic, urethane, polybutadiene, styrene butadiene, or ethylene propylene may be used alone or in combination, and reinforcing agents, flame retardants, vulcanizing agents, etc. Compositions are preferred. If more heat resistance than the above elastomers is required, use a heat-resistant elastomer consisting of synthetic rubbers such as chloroprene butyl rubber, halogenated butyl rubber, silicone rubber, and fluorine rubber, either singly or in combination, and use a reinforcing agent as well. A composition containing necessary ingredients such as , flame retardant, and vulcanizing agent is preferred.

Further, the ratio of filament to elastomer may be appropriately selected depending on the purpose and required characteristics, but for example, filament: elastomer = 90-40: 10-6.
A ratio (weight ratio) of 0 is used. In particular, in the present invention, the filaments are spread apart, so when impregnated with the above-mentioned elastomer solution, it penetrates well, and therefore monofilaments can be bonded uniformly with a small amount of elastomer, thereby relatively increasing the filament ratio. be able to. In particular, when the content ratio of filaments is 50% or more, it becomes possible to bring out unprecedentedly high strength properties. In order to have a high content ratio of filaments and to allow the elastomer solution to penetrate well between the monofilaments, the filaments must be opened sufficiently to incorporate the elastomer solution into the monofilaments, and then the excess elastomer must be removed using a sharp edge such as a doctor knife. If a method such as removing the elastomer is used, it is possible to increase the filament ratio and obtain a composite structure in which the filament and the elastomer are completely integrated.

The filling rate of the elastomer between the monofilaments is approximately 60% or more of the voids between the monofilaments,
In particular, it is preferable that 70 to 90% or more is filled with elastomer. If this filling rate is low, a homogeneous and highly reliable airbag cannot be obtained.

In addition to the dip coating method, methods for coating the filament with elastomer include dip coating in the form of a dispersion, and methods in which the elastomer is powder-injected or passed through a heated filament in an atmosphere in which it is scattered to melt and adhere. It can be carried out.

In the present invention, the tape or tape-like material may be wound into a bag shape by winding it around a mandrel having a predetermined size and shape. , rotating arm type, and other special types in which the arm or mandrel is wound with a special rotational movement can be applied.

Divided into shapes, there are three methods: wrapping closed shapes such as cocoons, spheres, and cones; winding cylindrical and disc shapes; and winding irregular shapes such as prisms and pyramids. It can also be applied by method.

Although there are various winding patterns, a predetermined strength can be imparted by broadly classifying them into parallel winding, helical winding, longitudinal winding, or a combination thereof. In cases where pressure is generated inside the bag, such as in an airbag, by forming the bag with a laminated structure of at least two or more layers with different winding directions, the pressure can be applied uniformly.

When molding into a removable shape, use a deformable hollow mandrel, such as a metal mandrel (which can be disassembled if necessary) or a rubber mandrel, and mold it into a closed shape. If so, use a consumable mandrel made of gypsum, rock salt, easily fused metal, etc. In order to easily remove the mandrel after molding, it is desirable to apply a mold release agent to the mandrel in advance.

When the elastomer is made of a rubber composition, it is desirable to perform a vulcanization treatment, and this vulcanization treatment involves fusion-welding the adjacent filaments in a crossing or parallel state with an elastomer that has previously covered the filaments. This is done to maintain the cut shape and protect the filament. The temperature condition is the temperature at which the elastomer covering the filament exhibits a predetermined adhesive force, that is, 120~
The temperature is preferably 190°C, and harsh conditions such as heating temperature 200″C1 heating time 20 minutes or more should be avoided in consideration of thermal decomposition of the elastomer.

[Effect]

When the airbag senses a vehicle impact and inflates and deploys, the gas for inflation and deployment preferentially flows into the thinner part that has less resistance to deformation, so it faces the passenger's waist and lower legs. The partial airbag starts to inflate first. Therefore, even if the vehicle suddenly decelerates during a collision or the like, it is possible to effectively prevent the occupant's hips and lower legs from moving forward in the vehicle due to inertia force.

〔Example〕

Examples of the present invention will be described below.

In Figure 1, 1 is 1500D of polyparaphenylene/3.4 diphenyl ether/terephthalamide;
A tape-shaped spread yarn obtained by aligning five 100OF yarns and opening them into a tow.The tape-shaped spread yarn 1 is passed through a rubber solution impregnating device 2 and After impregnation with rubber solution 3 in which a rubber composition having the formulation shown in Table 1 was dissolved in toluene, the amount of adhesion was controlled to 20 g 1 m 2 using a doctor knife 4. The arrow indicates the traveling direction of the tape-shaped spread fiber 1.

The rubber solution coated in this way has a thickness of 4 mm.
An extremely thin tape 5 having a width of 0 μm and 8 cylinders was obtained. An enlarged cross-section of this tape 5 is shown in FIG. Second
In the figure, 6 is a monofilament.

Then, the tape 5 is passed between opposing rollers 7.8, passed through rollers 9.10, and then passed through the disc-shaped mandrel 13.
A delivery eye 1 that reciprocates in a direction parallel to the rotation axis 12 of the
1, the part facing the hips and lower legs of the occupant (approximately 2 of the total surface area) is placed on a decomposable metal disk-shaped mandrel 13 coated with a release agent in advance.
5% of the total surface area) was thinner, and the other portions (approximately 75% of the total surface area) were wound slightly thicker. Specifically, the winding angle is 14.5°, and the tape feeding speed is 0.
．． After uniformly wrapping three layers of the tape 5 on the disc-shaped mandrel 13 at 45 m/sec, approximately 75% of the total surface area
Another layer was wrapped around the part corresponding to 4N. The above-mentioned FIG. 2 is an enlarged view of the cross section of the tape 51 and the edge of the disc-shaped mandrel 13.

Thereafter, the monofilaments were vulcanized under heating and pressure conditions of 180° C. and 10.5 kg/cmz to firmly adhere the monofilaments with rubber. Then, the disc-shaped mandrel 13 was disassembled and the airbag formed on the mandrel was taken out. FIG. 3 is a cross-sectional view of the maximum diameter portion of the airbag 14. As shown in FIG. In the figure, A indicates a thinner portion.

(Comparative Example) 2 Next, as Comparative Example 1, an airbag having the same overall thickness (corresponding to prior art (2)) was manufactured in the same manner as in the above example.

In addition, the number of tape windings in this case was four layers.

Furthermore, as Comparative Example 2, an airbag (corresponding to prior art (2)) having a partition inside was produced. The airbag of Comparative Example 2 has the same configuration as that shown in FIG. 6, and the manufacturing method is similar to that of the above example, with the number of tape wraps being 4 layers and the overall thickness of the airbag being the same. After obtaining the cloth partition 32 by the method, the cloth partition 32 is attached to the airbag 3.
It is sewn on one end of 1. The material of the partition body 32 may be any material as long as it is airtight and has flexibility so that it can be folded together with the airbag 31.

Regarding the three types of airbags produced as described above,
Table 2 below shows a comparison of storage volume ratio and knee protection ratio.

Table 2 In Table 2 above, the storage volume ratio and knee protection rate each indicate the following.

Storage volume ratio - Expressed as a ratio of the volume of the airbag when folded to that of Comparative Example 1, the smaller the volume, the better the absorption activity.

Knee protection rate - airbag inflation and deployment test 10
The test is performed 0 times and is expressed as a percentage of whether the part facing the passenger's waist and lower limbs inflated first.The higher the number, the higher the protection effect for the lower back and lower limbs.

As is clear from Table 2, the airbag according to the present example has a compact structure and has an excellent function of protecting the lower back and lower limbs of the occupant when an impact such as a vehicle collision is detected.

FIG. 4 shows that the airbag 14 according to this embodiment, which was housed in the steering wheel 15, is inflated and deployed to the occupant.
This shows how 6 is protected. In the figure, the direction of the arrow indicates the direction of gas flow. As shown in the figure, the gas first tries to flow into the area facing the occupant's waist and lower legs (the area towards the top), so this area expands first. Therefore, it is possible to prevent the occupant's waist and lower limbs from moving forward in the vehicle in the event of a vehicle collision or the like.

In addition, in the airbag of this embodiment, the thickness (L, ) of the thin part was set to 75% of the thickness (t2) of the thick part, but in order to enjoy the effects of the present invention, tl should be 90% of t2.
% or less. On the other hand, if the thickness of the airbag is too thin, it will not be able to exhibit the specified strength, so L is less than 5 of L2.
It is preferable to set it to 0% or more.

However, since the airbag of Comparative Example 1 has a uniform overall thickness b, the gas flow is the same as that shown in FIG. Flows upward and downward. For this reason,
It is not possible to reliably prevent the waist and lower limbs from moving forward of the vehicle in the event of a vehicle collision.

Furthermore, since the airbag 31 of Comparative Example 2 (prior art ■) has the partition body 32, as shown by the arrow in FIG.
Gas ejected into the airbag 31 when an impact is detected is blocked by the partition 32 and flows upward through the lower part of the airbag 31, so it expands from the part facing the occupant's waist and lower legs, causing the waist and lower legs to move toward the front of the vehicle. can be prevented from moving to.

However, the knee protection rate is slightly inferior to that of this embodiment, and since it includes the middle layer fabric, it is bulky and does not have good storage properties.

〔Effect of the invention〕

The airbag according to the present invention has a thickness that is thinner in the part facing the occupant's waist and lower legs when it is inflated and deployed than in other parts, so it is easy to store and can be used when the vehicle suddenly decelerates, such as during a vehicle collision. In this case, the portions that come into contact with the occupant's hips and lower legs expand first, so that the hips and lower legs can be reliably prevented from moving forward in the vehicle.

[Brief explanation of drawings]

Figure 1 is a side view of each step of manufacturing the airbag of the present invention, Figure 2 is an enlarged view of the cross section of the tape coated with rubber solution and the edge of the mandrel, and Figure 3 is the maximum diameter of the airbag of the present invention. 4 to 6 are views showing how the airbag inflates and deploys to protect vehicle occupants. The airbag in FIG. 4 is the one according to the present invention, and the airbag in FIG. The airbag shown in FIG. 6 is related to Prior Art I (Comparative Example I), and the airbag in FIG. 6 is related to Prior Art ■ (Comparative Example ■). 5... Tape, 6... Monofilament, 13... Disc-shaped mandrel, 14... Air bag Air bag 1 14 Figure 3 □ri 7Q 5 4 6 5 21 1A 6

Claims (1)

[Claims] An airbag in which the fiber filaments are arranged in a substantially linear and parallel manner or in which the tape is wound into a bag shape, when the airbag inflates and deploys, the surface of the occupant's waist and lower legs is exposed. An airbag characterized by a thinner part than other parts.