JP2502847B2 - Airbag cover body - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an airbag cover body which is ruptured by the expansion and expansion of a bag when the airbag is operated.

[0002]

2. Description of the Related Art Conventionally, as an airbag cover body, a skin material (skin layer) made of a soft synthetic resin is formed on the surface of a core material (core layer) made of a hard synthetic resin to give softness and feel. It has been proposed to improve the condition and prevent discomfort when it hits the body. (JP-A-1-202550) In the double-layered cover body disclosed in this publication, the breaking line is formed by providing slits in the core material, so that the breaking line portion has low hardness, Since it is only a skin material that uses a synthetic resin with low tensile strength, it is easily deformed, and the breaking force of the cover body is likely to rise due to the reaction force of the gas bag in the folded and compressed state, which may deteriorate the appearance. Is strong.

On the other hand, when the skin layer is a foam layer,
Even when pressed from the inside of the cover body, the bubbles inside the foam layer absorb and relieve the stress, the deformation of the layer is suppressed, the fracture line is difficult to appear on the surface, and the appearance can be improved. However, in the case of such a configuration, the adhesion between the core material layer and the skin layer is not sufficient, and there is a risk that both layers will peel off at the time of breakage to generate scattered matter.

There is also a proposal to improve the adhesion between the core material layer and the foam skin layer. That is, the core material layer is formed of a resin-impregnated fibrous sheet having pores communicating with the front and back sides, a hot-melt type adhesive is applied to this, and the foam sheet is integrated by vacuum forming, so that the adhesive force between the two is increased. It is to improve. (JP-A-1-12275
No. 4).

[0005]

DISCLOSURE OF THE INVENTION Problems to be Solved by the Invention
In the case of No. 754, a thin portion or a defective portion is provided in the foam layer as a weak portion which becomes a break portion, and the core layer is not reinforced with a small amount of resin impregnation or without impregnation in the thin portion or the defective portion. It is formed by forming a part.

However, this cover body is formed by thinning the broken portion of the foam layer from the skin layer side or by providing a cavity inside the foam body. Of course, when a cavity is provided inside, a break line appears on the outer surface of the cover due to shrinkage after molding, and the appearance is deteriorated.

Under the above circumstances, the present invention has no break lines on the outer surface, has a soft feeling, and has a sufficiently strong adhesive force between the core layer and the foam skin layer. An object of the present invention is to provide a highly reliable and lightweight airbag cover body that does not generate scattered matter at the time of breaking and can surely perform breaking along an assumed line.

[0008]

Means for Solving the Problems As a result of intensive studies, the present inventors have reached the present invention.

The gist of the present invention is to provide an airbag cover body having a rupture portion which is broken when the airbag is deployed, wherein the airbag cover body comprises a core layer made of a thermoplastic elastomer or thermoplastic resin having high hardness and a primer layer. And a skin layer made of integral skin type polyvinyl chloride foam that is integrated with the core layer by vacuum forming through, the fracture portion is formed as a thin portion in the core layer, and The airbag cover body is provided with a suction hole for molding.

The core layer in the present invention is composed of a thermoplastic elastomer or a thermoplastic resin having a high hardness, and examples of the thermoplastic elastomer include olefin-based,
Polyurethane-based, polyvinyl chloride-based, etc., and examples of the thermoplastic resin include ABS, polyolefin,
For example, polyvinyl chloride.

The skin layer used in the present invention must be made of integral skin type polyvinyl chloride foam. As is well known, this foam comprises an extremely thin skin layer and a foam layer which continuously changes so that the density thereof gradually decreases with distance from the skin layer integrated with the skin layer. The reason why the foam having such a structure is used for the skin layer in the present invention is as follows. When a non-foamed skin layer and a uniform foam layer are integrally bonded and used as the skin portion, the non-foamed skin layer 41 and the foam layer 42 have large physical property changes as shown in FIG. The crack A does not extend smoothly, the fracture is not performed along the assumed fracture line, and the small pieces are scattered as shown in FIG. 5 (plan view of the cover body). On the other hand, in the integral skin type foam of the present invention, as shown in FIG. 6, the change in physical properties from the foam layer 51 to the skin layer 52 is continuous, so that it smoothly follows the assumed break line. The crack A does not enter and no scattered matter is generated.

In the airbag cover body of the present invention, in order to sufficiently enhance the adhesive force between the core layer and the skin layer, both layers are firmly integrated with each other through the primer layer by the true molding.

In the present invention, the fractured portion is provided as a thin portion in the core layer. To further assure the fracture, the thinned portion is provided with a hole of about 1 mm. This hole also serves as a suction hole during vacuum forming. The suction hole for vacuum forming can be provided in an appropriate place other than the thin portion, if necessary.

[0014]

Embodiments of the present invention will now be described with reference to the drawings.

FIG. 2 is a front view of the airbag cover body of the present invention mounted on the steering wheel, and FIG. 1 is a sectional view taken along the line II--I of FIG. In FIG. 2, 1 is an airbag cover body, 1a is a skin layer, 1b is a core layer, 2 is a back,
Reference numeral 3 is an inflator, and 4 is a thin-walled portion serving as a breaking portion. FIG. 3 is a partially enlarged view of the broken portion, where 31 is a thin skin layer in the skin layer, 32 is an integral skin polyvinyl chloride foam layer, 33 is a primer layer, and 34 is a through hole. FIG. 7 is a perspective view of the core layer, and FIG. 8 is an enlarged explanatory view of the thin-walled broken portion.

The airbag cover body of the present invention can be molded as follows.

As shown schematically in FIG. 9, a vacuum forming machine 8
1, a core layer 82 formed of the hard material and coated with a primer and a urethane adhesive is set, and a heated polyvinyl chloride integral skin type foam sheet 83 descends to form a vacuum. After being molded, the airbag cover body of the present invention is molded.

[0018]

As described above, since the airbag cover body of the present invention is provided with the hole at the thin-walled breaking portion, the breaking can be performed more reliably and stably and the molding workability is improved. You can Further, in the present invention, the skin layer is an integral skin foam, and by solidly integrating with the core layer by vacuum molding with a primer layer interposed in the core layer, scattered matter does not occur at the time of breaking, The reliability can be increased. Further, the fracture portion was formed as a thin portion, but since the integral foam is present on the core layer, the fracture line does not appear on the surface,
It also has a soft texture and is excellent in appearance.

[Brief description of drawings]

1 is a cross-sectional explanatory view taken along the line I-I of FIG.

FIG. 2 is a front view of an airbag cover body of the present invention loaded on a steering wheel,

FIG. 3 is an enlarged explanatory view of a broken portion of an airbag cover body of the present invention,

FIG. 4 is an explanatory view of cracks when the conventional airbag cover body is broken,

FIG. 5 is an explanatory view of a crack on the surface of the airbag cover body,

FIG. 6 is an explanatory view of a crack when the airbag cover body of the present invention is broken,

FIG. 7 is a perspective view of a core layer in the airbag cover body of the present invention,

FIG. 8 is an enlarged explanatory view of the fracture portion,

FIG. 9 is an explanatory view of forming the airbag cover body of the present invention.

Claims (1)

(57) [Claims] 1. An airbag cover body having a rupture portion that ruptures when the airbag is deployed, wherein the airbag cover body is vacuum-formed via a core layer made of a thermoplastic elastomer or thermoplastic resin having high hardness and a primer layer. By a skin layer made of integral skin type polyvinyl chloride foam integrated with the core layer, the fracture portion is formed as a thin portion in the core layer, and the thin portion for vacuum forming An airbag cover body characterized in that a suction hole is provided.