JPH092180A - Air bag cover - Google Patents

Abstract

PURPOSE: To provide an air bag cover to facilitate formation of a break scheduled part even in a decoration sheet of three-layer structure having an skin layer and arranged on a core surface. CONSTITUTION: A folded air bag is covered with an air bag cover 10 and a break scheduled part 16 broken to protrude the air bag during expansion is formed, and comprises a core 11; and a decorative sheet 12 arranged on the surface side of the core 11. The decorative sheet 12 comprises a skin layer 13 on the surface side of the decorative sheet 12; a barrier layer 14 arranged on the back side of the decorative sheet 12 and for protection of the skin layer 13 during injection-molding of the core 11; and a foamed layer 15 located between the skin layer 13 and the barrier layer 14. The break scheduled part 16 comprises a recessed part 16a formed on the back side of the core 11; and a fixing part 16b fixed to the skin layer 13 with the barrier layer 14 forcibly spread.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an air bag cover for an automobile instrument panel, a door trim, a seat back, a steering wheel pad, etc., which covers a folded air bag of an air bag device. An airbag made of synthetic resin, in which a to-be-broken portion to be broken to project the bag is arranged, and a three-layered decorative sheet having an outer skin layer, a foam layer, and a barrier layer is arranged on the surface side of the core material. Regarding the cover.

[0002]

2. Description of the Related Art Conventionally, as an airbag cover of this type, a core material made of a synthetic resin and a decorative sheet provided on the surface of the core material in consideration of the design of the interior member in the peripheral portion are used. It was configured (see Japanese Utility Model Laid-Open No. 63-22262, etc.).

In order to make the airbag rupture when the airbag is inflated and to project the airbag, the airbag cover is
A part to be broken was formed. This portion to be broken was formed by forming a recess in the airbag cover by a processing jig using high frequency, heat, and ultrasonic waves (Japanese Patent Laid-Open No. 2-248).
238, JP-A-4-151345, JP-A-6-218811).

[0004]

If this recess is provided on the front surface side of the airbag cover, it will reduce the designability of the airbag cover, so it is provided on the back surface side, and
In order to break the airbag cover smoothly, it is necessary to provide it on the decorative sheet.

In this case, as the decoration sheet, an outer skin layer made of soft vinyl chloride or the like is arranged on the front surface side of the decoration sheet, and is arranged on the back surface side of the decoration sheet to prevent heat and injection pressure during injection molding of the core material. A sheet material in which a barrier layer made of polypropylene or the like for protecting the outer skin layer and a foam layer made of expanded polypropylene or the like interposed between the outer skin layer and the barrier layer for improving the feel are laminated and integrated. When using, it is necessary to provide not only the barrier layer but also the recessed portion on the back surface side of the outer skin layer.

However, the skin layer has a thickness of 1 mm.
The front and back are thin, and it is not easy to control the thickness of the outer skin layer when forming the recess. In particular, the airbag cover often has a curved surface due to the requirement of a design shape, and a portion to be fractured is formed on the curved surface, so that it is very difficult to control the thickness of the outer skin layer.

The present invention has been made to solve the above-mentioned problems, and provides an airbag cover which can be easily formed with a to-be-broken portion even on a decorative sheet having a three-layer structure and provided with an outer skin layer on the surface of a core material. The purpose is to do.

[0008]

An airbag cover according to the present invention comprises a core material and a decorative sheet arranged on the surface side of the core material, and the decorative sheet comprises:
An outer skin layer on the front surface side of the decorative sheet, a barrier layer disposed on the rear surface side of the decorative sheet for protecting the outer skin layer during injection molding of the core material, and interposed between the outer skin layer and the barrier layer. A synthetic resin airbag cover, which is configured to include a foam layer, and which covers a folded airbag and has a breakable portion to be broken to project the airbag when inflated. The breakable portion is configured by arranging a concave portion provided on the back surface side of the core material and a fixing portion that extends the barrier layer and fixes the barrier layer to the outer skin layer. To do.

[0009]

In the airbag cover according to the present invention, as the airbag is inflated, a recess is formed on the back surface side in the core material portion of the portion to be broken, so that stress is applied to that portion. Concentration easily occurs and breaks easily, and the barrier layer is thin in the portion of the decorative sheet that is to be broken, and stress concentration occurs in the barrier layer at that portion, and the barrier layer breaks,
Since the outer skin layer is fixed to the breakable barrier layer, the outer skin layer is broken together with the breakage of the barrier layer, and the planned breakage portion is smoothly broken.

The fixing portion of the decorative sheet is, for example,
From the back side of the decorative sheet, by simply pressing a processing blade such as an ultrasonic welder or high frequency welder slowly, the barrier layer is heated and softened, the foam layer is melted and disappears, and the barrier layer is welded to the outer skin layer as a thin wall. It can be formed easily by cooling in that state. Furthermore, at the time of this processing, even if the back surface side of the outer skin layer is recessed to reduce the wall thickness, it is sufficient to ensure that the outer skin layer has a predetermined thickness or more. As compared with the case where a concave portion is provided to deal with the problem, the thickness can be remarkably simplified as compared with the thickness management for ensuring the thickness within a certain range.

Therefore, in the airbag cover according to the present invention, the breakable portion can be easily formed even in the three-layered decorative sheet provided with the outer skin layer and arranged on the surface of the core material, and the airbag is inflated. At times, the airbag can be smoothly broken and the airbag can be projected.

[0012]

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

As shown in FIGS. 1 to 3, the airbag cover 10 of the first embodiment is formed as a part of an instrument panel (hereinafter abbreviated as instrument panel) 8 of a vehicle, and the instrument panel 8 is a instrument panel main body 9. And the airbag cover 10.

The instrument panel body 9 comprises a base material 9a made of a hard synthetic resin such as polypropylene containing a filler,
A decorative sheet 12 described later is provided to extend and a decorative sheet 9b arranged to cover the base material 9a.

The airbag cover 10 is arranged at a position to cover the folded airbag 2 of the airbag device 1, and comprises a core material 11 and a decorative sheet 12 arranged on the front surface side of the core material 11. It is configured.

The airbag device 1 will be described. The airbag device 1 includes a bag-shaped airbag 2 that is folded and stored, and a cylinder type inflator 3 that supplies inflation gas to the airbag 2. , A cylindrical diffuser 4 for diffusing gas from the inflator 3 and flowing into the airbag 2, and a box-shaped case 5 covering the airbag 2, the inflator 3, and the diffuser 4 There is.

Reference numeral 4a is a gas flow hole for diffusing the gas from the inflator 3 into the airbag 2 and inflowing it. Reference numeral 4b is a plurality of bolts projecting from the diffuser 4. These bolts 4b are By fixing the nut 6, the case 5, the airbag 2, and the diffuser 4 are integrated, and the airbag device 1 is attached and fixed to the bracket 7 protruding from the frame of the vehicle.

The side wall of the case 5 has a double structure including an inner panel 5a and an outer panel 5b. The outer panel 5b has a predetermined number of claws 5c that are cut and raised and extend toward the inner panel 5a. Are formed. These claws 5c lock a bracket 11a described later.

The airbag cover 10 is configured so that the breakable portion 16 is arranged in an "H" shape as viewed from above so that the two door portions 17 and 18 can be opened when the airbag 2 is inflated. There is. It should be noted that the position between the upper and lower ends of the “H” shape of the scheduled breakage portion 16 becomes the hinge portion 19 as the center of rotation when the door portions 17 and 18 are opened.

The core material 11 is a thermoplastic elastomer having compatibility with the base material 9a in order to secure the bending property of the hinge portion 19 without breaking and to secure the bonding force with the base material 9a. Are formed from. In the case of the examples, the base material 9a is formed of polypropylene containing a filler, and examples of the thermoplastic elastomer having compatibility with polypropylene include olefin-based thermoplastic elastomer and styrene-based thermoplastic elastomer. In the case of the examples, the core material 11 is formed of an olefinic thermoplastic elastomer.

Further, the core material 11 is provided on the back surface side of the outer peripheral edge,
A bracket 11a having a rectangular tube shape is provided so as to project, and a mounting hole 11b for inserting and locking the claw 5c of the case 5 of the airbag device 1 is formed in the bracket 11a. The bracket 11a includes the planned breakage portion 16 and the door portions 17 and 18,
It is formed to connect the portion of the airbag cover 10 to the case 5 of the airbag device 1 so as to be arranged accurately above the folded airbag 2.

The decorative sheet 12 has a skin layer 13 on the surface side.
And a barrier layer 14 disposed on the back surface side for protecting the outer skin layer 13 during injection molding of the core material 11, and a foam layer 15 interposed between the outer skin layer 13 and the barrier layer 14. It is configured. The barrier layer 14 also serves to protect the foam layer 15 when the core material 11 is molded.

In the case of the embodiment, the outer skin layer 13 is made of soft vinyl chloride, the barrier layer 14 is made of the same olefinic thermoplastic elastomer as the core material 11, and the foam layer 15 is made of expanded polypropylene. There is. The outer skin layer 13 has a wall thickness of 0.7 mm, the barrier layer 14 has a wall thickness of 1.0 mm, and the foam layer 15 has a wall thickness of 3.0 mm.

A recess 16a is formed in the core material 11 at the portion to be broken 16 and a fixing portion 16b is formed on the decorative sheet 12 by pressing the barrier layer 14 and fixing the barrier layer 14 to the outer skin layer 13. ing.

The recess 16a and the fixing portion 16b may be formed continuously or intermittently along the "H" shape of the breakable portion 16.

The thin portion 14a of the barrier layer 14 in the fixed portion 12 has a thickness of 0.1 to 0.3 mm.
And This is because if the wall thickness is less than 0.1 mm, there is a risk of breakage during processing, and if the wall thickness exceeds 0.3 mm, the breaking strength increases and the spreading performance decreases.

The airbag cover 10 and the instrument panel 8
First, the sheet-shaped decorative sheet 12 including the portion of the decorative sheet 9b is vacuum-formed into a predetermined shape to be embedded in the instrument panel 8, and then, as shown in the upper stage of FIG. , From the back side of the decorative sheet 12,
By pressing the processing blade C1 of the ultrasonic welder,
b is formed. In this process, pressure of about 200 KPa and 50
The processing blade C1 is pressed against the barrier layer 14 at a slow descending speed of about mm / min. Then, the barrier layer 14 is heated and softened, the foam layer 15 is melted and disappears, and the thin portion 14a is formed on the barrier layer 14, and the thin portion 14a can be welded to the outer skin layer 13 and cooled in that state. Then, the fixing portion 16b can be easily formed.

Then, the decorative sheet 12.9b having the fixed portion 16b formed into a predetermined shape is set in a molding die for injection-molding the base material 9a of the instrument panel body 9 to form the base material 9a.
To form

After that, the core material 11 of the airbag cover 10
Set it in the injection mold of and, as shown in the middle of Fig. 4,
The core material 11 is formed.

Then, after the mold release, as shown in the lower part of FIG. 4, the recess 16 is formed by using the processing blade C2 of the ultrasonic welder.
The instrument panel 8 can be manufactured by forming a and further forming the mounting hole 11b in the bracket 11a of the core material 11.

Since the base material 9a, the core material 11, and the barrier layers 14 of the decorative sheets 9 and 12 have the same kind or compatibility with each other, they are strong without using an adhesive. Will be joined to.

In addition, when the fixing portion 16b and the concave portion 16a are formed, the fixing portion 16b and the concave portion 16a are formed by using not only an ultrasonic welder but also a heated cutter or a high frequency cutter. May be. Further, recess 1
When forming 6a, the core material 11 may be formed simultaneously with the core material 11 at the time of injection molding of the core material 11 by the mold surface of the molding die.

After the instrument panel 8 is manufactured, when the instrument panel 8 is mounted on a vehicle and then connected to the airbag apparatus 1, the inner panel 5a in the case 5 of the airbag apparatus 1 integrated by using the bolts 4b is integrated. The bracket 11a is inserted between the outer panel 5b and each of the claws 5c to be inserted and locked in the mounting hole 11b, and the airbag device 1 is attached to the instrument panel 8.
When the bracket 7 is fixed to the bolts 4b by the nut 6 and the other end of the bracket 7 is fixed to a frame (not shown), the airbag device 1 can be attached to the vehicle by connecting to the instrument panel 8. . It should be noted that when the instrument panel 8 is mounted on the vehicle, a predetermined instrument or the like is provided.

When the gas from the inflator 3 is discharged at a predetermined time, the gas is flown into the airbag 2 through the gas flow holes 4a of the diffuser 4, and the airbag 2 is broken at a portion 16 to be broken. Let the hinge part 19
The door parts 17 and 18 are opened with the center of rotation as the center of rotation, and the door parts 17 and 18 largely project from the instrument panel 8. The part to be broken 16
At the time of rupture, the recessed portion 16 is formed on the back side of the core material 11.
Since a is formed, stress concentration occurs at that portion and is easily broken. Further, at the portion of the decorative sheet 12, the thin portion 14a is formed in the barrier layer 14, and the stress concentration occurs at the thin portion 14a. The barrier layer 14 is ruptured due to the occurrence of cracks, and the outer skin layer 13 is made of soft vinyl chloride and easily extends. As a result of the fracture, the welded portion 13a is fractured integrally with the thin portion 14a, and the expected fracture portion 16 is smoothly fractured.

As described above, in the airbag cover 10 of the first embodiment, the fixing portion 16b of the decorative sheet 12 is
The barrier layer 14 is heated and softened by simply pressing the processing blade C1 such as an ultrasonic welder or a high-frequency welder from the back surface side of the decorative sheet 12, and the foam layer 1
5 is melted to make the barrier layer 14 thin and the outer skin layer 13
If it can be welded to the substrate and cooled in that state, it can be easily formed. And at the time of this processing,
Even if the back surface side of the outer skin layer 13 is recessed to reduce the thickness of the outer skin layer 13, it is sufficient to process the outer skin layer 13 so that the thickness of the outer skin layer 13 is not less than a predetermined value. This is much simpler than the thickness control for ensuring the thickness within a certain range when dealing with the problem, and the same effect as described in the section of the action and effect of the invention described above can be obtained.

Incidentally, the airbag cover 10 of the first embodiment.
Then, in the case where the core member 11 is provided with the bracket 11a that is connected to the case 5 of the airbag device 1 in order to properly dispose the planned breakage portion 16 and the door portions 17 and 18 above the folded airbag 2. However, if the airbag cover 10 is disposed above the airbag 2 with high accuracy, like the airbag cover 20 of the second embodiment shown in FIG. 5,
It is not necessary to provide a bracket for connecting to the case 5.

Further, in each embodiment, the airbag cover 1
Although the number 0 to 20 is used for the instrument panel 8, the present invention can be used for door trims, seat backs, steering wheel pads, etc. arranged to cover airbags of airbag devices other than instrument panels. You can

[Brief description of drawings]

FIG. 1 is an enlarged sectional view showing a main part of a first embodiment of the present invention.

FIG. 2 is a perspective view of the embodiment.

FIG. 3 is a sectional view showing a mode of use of the embodiment.

FIG. 4 is a diagram showing a process of processing a to-be-broken part of the embodiment.

FIG. 5 is a cross-sectional view showing a mode of use of the second embodiment.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 ... Airbag apparatus, 2 ... Airbag, 10 * 20 ... Airbag cover, 11 ... Core material, 12 ... Decorative sheet, 13 ... Outer skin layer, 14 ... Barrier layer, 14a ... Thin part, 15 ... Foam layer, 16 ... Breakable portion, 16a ... Recessed portion, 16b ... Fixed portion.

Claims (1)

[Claims] 1. A core material and a decoration sheet arranged on the front surface side of the core material, wherein the decoration sheet is provided on an outer skin layer on the front surface side of the decoration sheet and on a back surface side of the decoration sheet. The barrier layer is disposed and is provided with a barrier layer for protecting the outer skin layer at the time of injection molding of the core material, and a foam layer interposed between the outer skin layer and the barrier layer, and is folded. An airbag cover made of a synthetic resin, which covers an airbag and has a breakable portion that breaks in order to project the airbag when inflated, wherein the breakable portion is provided on the back surface side of the core member. An air bag cover, comprising: a concave portion that is formed and a fixing portion that extends the barrier layer and fixes the barrier layer to the outer skin layer.