JP2896256B2 - Airbag storage cover - 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 storage cover.

[0002]

2. Description of the Related Art Heretofore, there has been an airbag cover body in which a foamed polyurethane reinforced net is inserted.
However, in this case, it is troublesome to insert the reinforcing net into the foamed polyurethane molding die, and it is difficult to bury the reinforcing net uniformly. Therefore, the core layer is formed of a synthetic resin that is relatively hard and has sufficient tensile strength for shape retention and strength assurance, and the surface is coated with a soft synthetic resin that has a good appearance and feel. It has been proposed (JP-A-2-220945).

[0003]

By the way, a fragile portion is formed in this cover, but the fragile portion normally retains its shape at normal times, and when the bag is inflated in an accident, it is quickly and scheduled. Must be broken along the broken line.

As a structure of such a fragile portion, FIGS.
One such as shown at 0 is conceivable. FIG. 7 shows a case where only the core layer is thinned. However, since the skin layer remains on the thin core layer, it is slightly too strong to satisfy the above-mentioned required performance. FIG. 8 shows a case in which the core layer is completely removed. However, with this, the strength of the airbag storage cover body is not sufficient, and it is difficult to hold the insert when the skin layer is formed.

[0005] Therefore, it is recommended that the core layer as shown in FIG. 10 be made thinner and be protruded from the skin layer side to make the skin layer thinner. However, if the projecting portion of the mold is formed to have an acute cross-sectional structure in order to obtain the structure shown in FIG. 10, the durability is poor and it is not suitable for mass production, so that the projecting portion has a trapezoidal shape as shown in FIG. It is preferable to use a mold having

However, when the skin layer is formed by inserting the core layer into a mold having a trapezoidal protrusion after forming the core layer, the heat and injection pressure of the resin flow for forming the skin layer causes the skin layer to be molded as shown in FIG. The thin portion of the core layer may be softened or deformed, resulting in poor appearance or a defective product that does not break as designed. Further, even when the thin portion is molded without deformation, the thin portion is deformed as if the thin portion bulged upward as shown in FIG. 11 by the reaction force of the bag densely folded inside the airbag storage cover body, There is also a problem that the thin portion is seen as a raised line from the outside, which is not preferable in design.

Therefore, the present invention provides a good-looking airbag storage cover body that can be quickly and reliably broken along a predetermined breaking line in an emergency and that does not bulge at the breaking line in normal times. The purpose is to do so.

[0008]

Means for Solving the Problems As a result of intensive studies on the structure of the broken portion, the present inventors have found that the problem can be solved by devising the structure of the protruding wall projecting from the core layer side to the skin layer. Heading, and led to the present invention.

That is, the present invention has a two-layer structure having a soft synthetic resin skin layer on the front surface and a synthetic resin core layer harder than the skin layer on the back surface, and forms a break portion for bag deployment. In the airbag storage cover body, the break portion is formed by a protruding surface portion that protrudes from the core layer into the thickness of the skin layer, and the protruding surface portion includes a protruding wall portion on both sides and a flat plate portion connecting therebetween, An airbag storage cover body characterized in that a thin-walled break portion is formed on the side of the projecting wall opposite to the projecting wall facing the molten resin flow at the time of molding the skin layer.

The structure of the break portion of the airbag housing cover of the present invention is important, and other requirements are not particularly limited. For example, a soft synthetic resin is used for the skin layer used for the cover body of the present invention, and a synthetic resin harder than the skin layer is used for the core layer.

In the above two layers, the following combinations may be mentioned as preferred examples.

Example 1 Type of resin Shore A Molding temperature Hardness Skin layer Thermoplastic styrene-based elastomer 45 200 ° C. Core layer Thermoplastic styrene-based elastomer 90 240 ° C. Example 2 Skin layer Thermoplastic styrene-based elastomer 40 200 ° C. Core layer Thermoplastic olefin Elastomer 90 220 ° C Example 3 Skin layer Foamed polyurethane 70 100 ° C Core layer Thermoplastic urethane elastomer 85 222 ° C The thermoplastic elastomer is TP manufactured by Sumitomo Chemical Co., Ltd.
It is commercially available as an E-SB series or the like.

[0013]

An embodiment of the present invention will be described with reference to FIGS.

In FIG. 1, reference numeral 1 denotes an airbag storage cover.
The core layer 2 is formed of, for example, a thermoplastic olefin elastomer, and the skin layer 3 is formed of a thermoplastic styrene elastomer. 4 is a broken part in FIG.
It is formed in a substantially H shape as shown in FIG. FIG. 2 is an enlarged cross-sectional explanatory view of the break portion 4. As shown in FIG. 2, the fractured portion has a protruding surface 5 protruding from the core layer 2 into the thickness of the surface layer 3.
The protruding surface portions are formed on the protruding wall portions 6 and 7 on both sides.
And a flat plate portion 8 connecting between them, and a thin break portion 9 is formed on the protruding wall portion 7.

In the present invention, when the skin layer 3 is formed, the thin-walled rupture portion 9 forms a wall portion on the opposite side of the projecting wall portion 6 serving as a resin flow receiving surface with respect to the flow direction A of the skin layer molten resin. 7
Must be formed.

By forming the break portion in such a structure, when the core layer is inserted into the mold for forming the skin layer to form the skin layer 2, the molten resin flow A has a relatively thick protrusion. Since it is received by the wall portion 6 and the flat plate portion 8 is similarly set to be relatively thick, there is no molding defect that the inserted core layer is deformed as in the related art.

Further, since the thin portion 9 is not formed over the entire width of the flat plate portion 8, there is no problem that the breaking line rises as shown in FIG.

FIG. 3 shows an example of the structure of the break portion of the present invention.
Various modifications are conceivable as shown in FIGS.

[0019]

As described above, the airbag storage cover body of the present invention has no appearance defect since the broken portion does not deform when the skin layer is formed, and has the same design as in an emergency. It can be broken quickly and reliably along the breaking line.

Further, even if the airbag folded tightly inside receives the reaction force, the broken portion does not rise, so that no broken line appears on the surface of the cover body.

[Brief description of the drawings]

FIG. 1 is a partial cross-sectional perspective view of an airbag storage cover body of the present invention.

FIG. 2 is an enlarged sectional explanatory view of a broken portion.

FIG. 3 is an enlarged sectional explanatory view showing the structure of another break portion.

FIG. 4 is an enlarged cross-sectional explanatory view showing the structure of still another break portion.

FIG. 5 is an enlarged cross-sectional explanatory view showing the structure of still another break portion.

FIG. 6 is an explanatory view of deformation of a conventional fractured portion by a resin for forming a skin layer.

FIG. 7 is an enlarged cross-sectional view showing the structure of a conventional break portion.

FIG. 8 is an enlarged cross-sectional view showing a structure of a conventional break portion.

FIG. 9 is an enlarged cross-sectional view showing the structure of a conventional break portion.

FIG. 10 is an enlarged cross-sectional view showing the structure of a conventional break portion.

FIG. 11 is an explanatory view of a state in which a conventional rupture portion is pushed from the inside of a cover body to generate a swell.

────────────────────────────────────────────────── ─── Continuation of the front page (56) References JP-A-2-220945 (JP, A) JP-A-3-189252 (JP, A) JP-A-2-220946 (JP, A) JP-A-2-220 171362 (JP, A) JP-A-1-202550 (JP, A) JP-A-4-163255 (JP, A) JP-A-63-101255 (JP, U) JP-A-63-201862 (JP, U) (58) Field surveyed (Int. Cl. ⁶ , DB name) B60R 21/16-21/32

Claims (1)

(57) [Claims] 1. An airbag housing having a two-layer structure having a soft synthetic resin skin layer on the front surface and a synthetic resin core layer harder than the skin layer on the back surface, and forming a break portion for bag deployment. In the cover body, the break portion is formed by a projecting surface portion projecting from the core layer into the thickness of the skin layer, the projecting surface portion includes projecting wall portions on both sides and a flat plate portion connecting between the projecting wall portions, and the skin layer An airbag storage cover body, wherein a thin break portion is formed on a protruding wall portion side opposite to a protruding wall portion facing a molten resin flow during molding.