Air bag

Description: TECHNICAL FIELD [Detailed description of the invention]

【0001】

[Industrial application field]

The present invention relates to an airbag for protecting an occupant in the event of a vehicle collision, and more particularly to an airbag having an improved impact absorption capacity of an elastomer airbag.

【0002】

[Conventional technology]

The airbag device is for deploying the airbag to protect the occupant in the event of a vehicle collision.

【0003】

Conventionally, airbags are generally composed of woven fabrics of fibers such as polyamide fibers coated with silicone rubber, but in recent years, as an alternative to this, airbags made of resin film (Japanese Patent Laid-Open No. 2-31965). ) And elastomer airbags (Japanese Patent Laid-Open No. 4-266544) have been proposed.

【0004】

[Problems to be Solved by the Invention]

However, the resin film has a drawback that the hardness is relatively high, and also has a problem that the strength, particularly the tear strength is low. For this reason, in a resin film airbag, it is necessary to increase the thickness of the film considerably in order to have sufficient durability against the stress applied during deployment by the inflator. Therefore, the resin film airbag is not practical because it becomes bulky when folded.

【0005】

Evaporative film airbags have higher tear strength and elongation than hard films, so they have sufficient durability for deployment by inflators, but as a result of collision tests, they are high when a dummy collides with the deployed airbag. It was observed that the airbag inflated due to the elongation, in other words, the low modulus, and the dummy could not be received, that is, the dummy hit the steering wheel and the instrument panel behind the airbag.

【0006】

In order to prevent this phenomenon, it is necessary to increase the hardness of the elastomer film to suppress the elongation, or to increase the thickness of the film in order to increase the modulus. However, if the hardness of the film is increased, the feel when the occupant thrusts into the airbag becomes hard, and it becomes difficult to fold the film, which reduces workability and at the same time increases the bulk of the airbag after folding. ..

【0007】

Increasing the thickness of the film also makes the occupant feel harder. Further, when the thickness of the film is increased, the bulk of the airbag becomes large, and as a result, the airbag device becomes large.

【0008】

For this reason, with regard to airbags made of elastomer film, it is possible to sufficiently absorb the impact when an occupant thrusts into the airbag without increasing the hardness of the film or increasing the film thickness. Is an issue.

【0009】

The present invention has been made in view of the above-mentioned conventional circumstances, and an object of the present invention is to provide an airbag having excellent energy absorption performance by regulating excessive expansion of an elastomer film airbag.

【0010】

[Means for solving problems]

The airbag of the present invention is characterized in that, in an airbag made of an elastomer film, a resin film is attached so as to cover a part of the elastomer film.

【0011】

[Action]

Resin films have less elongation than elastomer films. Therefore, when an occupant thrusts into the developed airbag of the present invention, the elongation of the elastomer film at the portion to which the resin film is attached is restricted. In addition, the elastomer film in the portion where the resin film is not attached stretches and absorbs the impact.

【0012】

[Example]

Hereinafter, examples of the present invention will be described in detail with reference to the drawings.

【0013】

FIG. 1 is a front view showing a front panel of an airbag for a driver's seat according to an embodiment of the present invention.

【0014】

The front panel 1A shown in FIG. 1A is a circular elastomer film 2 to which a resin film 3A having a slightly smaller diameter is attached to the center.

【0015】

In the front panel 1B shown in FIG. 1B, an annular resin film 3A having substantially the same outer diameter is attached to the outer peripheral portion of the circular elastomer film 2.

【0016】

The front panel 1C shown in FIG. 1C is a circular elastomer film 2 to which a cross-shaped resin film 3C having an appropriate width is attached.

【0017】

For the front panel 1D shown in FIG. 1 (d), four quarter-circular fan-shaped resin films 3D are attached to a circular elastomer film 2 so that a cross-shaped portion having an appropriate width is exposed. It is a thing. The front panel 1E shown in FIG. 1 (e) is a circular elastomer film 2 to which a resin film 3E having a cross shape and a ring shape is attached.

【0018】

The front panel 1F shown in Fig. 1 (f) consists of four quadrant fan-shaped resin films 3F so that the circular elastomer film 2 is exposed to the part having a shape that combines a cross shape and a ring shape. It is pasted.

【0019】

When the driver's seat airbag is manufactured by the present invention, the front panel as shown in FIGS. 1 (a) to 1 (f) is superposed on the front panel and the circular rear panel having the same diameter, and these panels are superposed. Join (eg, bond, weld) the periphery of the. This rear panel has an opening for receiving an inflator and a vent hole.

【0020】

In this case, the rear panel may be composed of only the elastomer film, or may be the one in which the resin film is attached to the elastomer film as shown in FIGS. 1 (a) to 1 (f).

【0021】

The configurations shown in FIGS. 1 (a) to 1 (f) are examples of the present invention, and the present invention is not limited to the illustrated ones as long as the gist thereof is not exceeded. For example, as the shape of the resin film to be attached to the elastomer film, various other shapes can be adopted. Further, the resin film may not be attached to the front panel, and the resin film may be attached only to the rear panel. Further, when a resin film is attached to an elastomer film is used for both the front panel and the rear panel, the shape of the attached resin film may be different between the front panel and the rear panel. It is preferable that the front panel obtained by attaching the resin film to the elastomer film has the resin film attachment surface side inside the airbag. This is because the surface of the airbag becomes flat.

【0022】

FIG. 3 is a perspective view of the passenger seat airbag 4 according to the embodiment, and FIG. 4 is a developed view of the passenger seat airbag 4. The passenger airbag 4 is composed of a center panel 5 and side panels 6 and 6, and has an opening 7 at the rear for receiving gas from the inflator. A ramp portion 8 for attaching the airbag 4 to a container (not shown) is provided around the opening 7. 9 is a vent hole.

【0023】

The center panel 5 and the side panels 6 and 6 are made by sticking resin films 5B and 6B on the inner surface of the airbag of the elastomer films 5A and 6A. The resin films 5B and 6B are provided mainly along the edges of the center panel 5 and the side panel 6, but may be provided at other locations.

【0024】

In the present invention, a thermoplastic elastomer and / or a rubber-based elastomer can be used as the elastomer film, and among these, the thermoplastic elastomer film is urethane-based, ester-based, olefin-based, or polyfluorocarbon-based. , Styrene-based, 1,2-polybutadiene-based, amide-based, chlorinated polyethylene-based, and their mixed films, and those with a laminated structure. Rubber-based elastomer films include butadiene-based and chloroprene-based films. , Acrylic films and films of these rubber-based elastomers, or films having a structure in which a thermoplastic elastomer and a rubber-based elastomer film are laminated can be used. The thickness of such an elastomer film is determined by the physical characteristics, particularly the balance of breaking strength, breaking elongation, tear strength and initial modulus, and cannot be unconditionally determined. There is a problem of deterioration of the tactile sensation and increase in bulk, and if it is too thin, the modulus will be insufficient. Therefore, it is preferably about 0.1 to 0.6 mm, particularly 0.2 to 0.4 mm.

【0025】

As the resin film, a film such as polyester, polypropylene, ethylene vinyl alcohol, polyamide, polybutylene terephthalate or the like can be used. If the thickness of such a resin film is too thin, the effect of restricting expansion of the elastomer film by providing the resin film cannot be sufficiently obtained, and if it is too thick, the airbag becomes bulky. Therefore, the resin film is preferably 0.05 to 0.15 mm, particularly preferably about 0.01 to 0.1 mm.

【0026】

In order to attach such a resin film to the elastomer film, it is preferable to adhere or weld it with an adhesive.

【0027】

The present invention will be described in more detail below with reference to experimental examples.

【0028】

Experimental example 1 As shown in Fig. 1 (a), each of the front panel base cloth and rear panel base cloth with a diameter of 700 mm made of thermoplastic polyurethane (TPU: "Tufretan 390S30D" manufactured by Nippon Valker Industries) film (thickness 0.3 mm) A circular polybutylene terephthalate resin (PBT: manufactured by Okura Industrial Co., Ltd.) film (thickness 0.04 mm) having a diameter of 525 mm was attached with an adhesive. A test airbag was prepared by adhering the front panel and the rear panel so that the PBT film surface was on the inside.

【0029】

The rear panel was provided with an opening for receiving an inflator having a diameter of 100 mm in the center, and two vent holes having a diameter of 20 mm were provided at a position 148 mm away from the center.

【0030】

Using the airbag produced in this way, the energy absorption capacity of the airbag was evaluated by the following method using the impact test apparatus shown in FIG. As an index of energy absorption capacity, the maximum acceleration (G) of impactor deceleration as the ability to stop the impactor, the amount of kinetic energy absorbed by the impactor, and the maximum value of the internal pressure of the airbag when the impactor collides. Was used.

【0031】

That is, the test airbag 10 is attached to the steering wheel 11. The thread 12 is pneumatically launched at a predetermined speed shown in Table 1, and the inflator (not shown) is ignited to deploy the airbag 10. The airbag 10 is made to collide with the impactor 14 (weight 30 kgf) held by the support 13. At this time, the coordinate portion was placed on the thread 12, and the acceleration of deceleration of the impactor 14 and the internal pressure of the airbag were recorded and analyzed to obtain the above index. The results are shown in Table 1.

【0032】

Experimental example 2 On the front panel side, as shown in Fig. 1 (b), instead of the circular PBT film, an annular PBT film (thickness 0.04 mm) with an outer diameter of 700 mm and an inner diameter of 370 mm was used, except that it was used. An airbag was prepared in the same manner as in Experimental Example 1, and an evaluation test of energy absorption capacity was conducted in the same manner. The results are shown in Table 1.

【0033】

Comparative Experimental Example 1 Airbags were prepared in the same manner as in Experimental Example 1 except that the PBT film was not attached to both the front panel side and the rear panel side, and the energy absorption capacity evaluation test was conducted in the same manner. The results are shown in Table 1.

【0034】

Comparative Experiment Example 2 An airbag was prepared in the same manner as in Comparative Experimental Example 1 except that a PBT film was used instead of the TPU film, and an energy absorption capacity evaluation test was conducted in the same manner. The results are shown in Table 1.

【0035】

[table 1]

<img file="JPH07291069A_D0001.tif" />【0036】

The following is clear from Table 1. That is, in an airbag containing only a TPU film (Comparative Experimental Example 1), when an impactor collides with a deployed airbag, acceleration is applied in the deceleration direction to decelerate, but due to the elastic physical properties of the TPU film, the impactor air Since the airbag expands in response to biting into the bag, the resistance to stop the impactor is insufficient, and the impactor collides with the steering wheel and is stopped suddenly.

【0037】

Therefore, the maximum acceleration of deceleration of the impactor is as large as 93.95G. In addition, sufficient resistance was not obtained to stop the impactor, the internal pressure of the airbag was 36.5KPa, and the amount of energy absorbed was as low as 952.1J.

【0038】

On the other hand, in Experimental Examples 1 and 2 in which the PBT film was attached, excessive expansion of the airbag was regulated without impairing the elasticity of the TPU, the internal pressure of the airbag was kept higher, and the impactor was used for steering. Since it can be received without collision, the maximum acceleration of deceleration of the impactor is less than half that of Comparative Experimental Example 1, and the amount of energy absorbed is also increased.

【0039】

The PBT film airbag was destroyed when the airbag was deployed.

【0040】

[Effect of the invention]

As described in detail above, according to the airbag of the present invention, there is provided an elastomer airbag having high energy absorption capacity and excellent occupant protection effect.

[Simple explanation of drawings]

[Figure 1]

It is a front view which shows the front panel of the driver's seat airbag which concerns on embodiment of the airbag of this invention.

[Figure 2]

It is a block diagram which shows the impact test apparatus used in the experimental example.

[Fig. 3]

It is a perspective view of the passenger seat airbag which concerns on embodiment.

[Fig. 4]

It is a top view which shows the panel of the airbag of FIG.

[Explanation of symbols]

1A, 1B, 1C, 1D, 1E, 1F front panel 2 Elastomer film 3A, 3B, 3C, 3D, 3E, 3F resin film