JP3254973B2 - Airbag 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 cover made of a synthetic resin, such as an instrument panel, a door trim, a seatback, and a steering wheel pad of an automobile, which covers a folded airbag of an airbag device.

[0002]

SUMMARY OF THE INVENTION The present invention can be easily manufactured even if a skin layer having a high design effect and a good feel is provided on the outer surface, and can be easily broken when the airbag is inflated. An object of the present invention is to provide an airbag cover capable of largely inflating the airbag.

[0003]

SUMMARY OF THE INVENTION An airbag cover according to the present invention is an airbag cover made of a synthetic resin for covering an airbag and breaking a portion to be broken when the airbag is inflated. It is arranged on the sheet and the back side,
A core material formed by injection molding with the decorative sheet as an insert, the decorative sheet, a skin layer disposed on the outer surface, and disposed on the back side of the skin layer,
For protection of the skin layer during injection molding of the core material
A barrier layer having a higher tensile strength than the skin layer, and a foam layer interposed between the skin layer and the barrier layer,
The core material is made of a thermoplastic elastomer that can be thermally fused to a barrier layer, and the breakable portion is formed in the barrier layer and the core material.
The breakable portion is characterized in that a tensile weak portion is formed intermittently or continuously.

[0004] In the airbag cover, in the skin layer, not to want to form the tensile weakness of the breakable portion.

[0005]

In the airbag cover according to the present invention, the decorative sheet is composed of a skin layer, a barrier layer, a skin layer and a burr.
Even if it is provided with three layers of a foam layer interposed between the core layer and the a layer, the tensile weak portion is formed intermittently or continuously in the core material on the back side and the barrier layer of the decorative sheet. Therefore, when a tensile force acts upon inflation of the airbag, the core material and the barrier layer are easily broken at the weakened portion, and the airbag can be greatly inflated from the opening generated by the breaking.
In addition, since the foamed layer has a low tensile strength, it may break the core material or the like.
Breaks easily at the part where

By the way, even if the skin layer is not provided with a tensile weak portion, the barrier layer has a higher tensile strength than the skin layer. Therefore, if the barrier layer is broken, the skin layer is smoothly broken following the breakage. . Of course, if the skin layer is also provided with a tensile weak portion, the skin layer will be more smoothly broken.

In the airbag cover according to the present invention, the core material on the back side is formed by injection molding from a thermoplastic elastomer which can be thermally fused to the barrier layer. It can be easily manufactured without using an adhesive or the like simply by setting a mold as an insert, and after injecting the mold, injecting a thermoplastic elastomer into the cavity.

[0008] Of course, the skin layer of the decorative sheet is protected by a barrier layer provided on the back surface side, and can be prevented from being damaged by heat or pressure during injection molding of the core material.

Therefore, the airbag cover according to the present invention can be easily manufactured even if the skin layer having a high design effect and good feel is provided on the outer surface, and can be smoothly formed when the airbag is inflated. The airbag can be largely inflated by breaking.

[0010] Further, if the skin layer is provided with a tensile weak portion, the airbag can be more clearly broken when inflated, and the airbag can be inflated smoothly.

Furthermore, an airbag cover can be manufactured only by setting a decorative sheet in a core injection molding die and performing injection molding. Therefore, even if the size is increased, the core injection molding die is increased in size. Just by doing so, it can be easily dealt with and manufactured.

Further, since the core material made of thermoplastic elastomer is formed by injection molding, the molding cycle is shorter than that of an airbag cover manufactured using a material such as urethane, and the efficiency is reduced in about half the time. Can be manufactured well.

Further, since the core material is formed of a thermoplastic elastomer that can be thermally fused to the barrier layer of the decorative sheet, the bonding strength with the decorative sheet is increased, and the decorative sheet together with the core material when the airbag is inflated. Even if it breaks, the decorative sheet can be prevented from peeling off from the core material.

Further, since the core material is formed of a thermoplastic elastomer, it is not necessary to separately embed a rigid member for maintaining the shape as compared with the case where a material such as urethane is used.

Further, in the decorative sheet , a foam layer is interposed between the skin layer and the barrier layer, so that the feel is further improved.

[0016]

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

The airbag cover 10 of the embodiment is shown in FIG.
3, the instrument panel 8 is formed as a part of an instrument panel (hereinafter, abbreviated as an instrument panel) 8. The instrument panel 8 includes an instrument panel body 9 and an airbag cover 10.

The instrument panel body 9 includes a base material 9a formed of a hard synthetic resin such as a polypropylene containing a filler;
And a decorative sheet 9b which is extended so as to cover the base material 9a.

The airbag cover 10 is disposed at a position that covers the folded airbag 2 of the airbag device 1 and includes a core 11 and a decorative sheet 12 disposed on the surface of the core 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 housed, and a cylinder-type inflator 3 that supplies gas for inflation 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 periphery of the airbag 2, the inflator 3 and the diffuser 4. I have.

Reference numeral 4a denotes a gas flow hole through which gas from the inflator 3 is diffused into the airbag 2 and flows therethrough. Reference numeral 4b denotes a plurality of bolts protruding from the diffuser 4, and 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 a bracket 7 protruding from a vehicle frame.

The case 5 has a side wall portion formed as a double structure of an inner panel 5a and an outer panel 5b. The outer panel 5b has a predetermined number of claws 5c which 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 such that the breakable portions 16 are arranged in an "H" shape when viewed from above, and the two door portions 17 and 18 are opened when the airbag 2 is inflated. I have. In addition, the position between the upper and lower ends of the “H” shape of the breakable portion 16 becomes the hinge portion 19 as a rotation center portion when the door portions 17 and 18 are opened.

The core member 11 can be formed by injection molding, and is formed of a thermoplastic elastomer in order to ensure that the hinge portion 19 bends without breaking. Further, in the case of the embodiment, In order to secure the bonding strength with the base material 9a, the base material 9a is formed of a thermoplastic elastomer having compatibility with the base material 9a. By the way, in the case of the embodiment, the base material 9a is formed of polypropylene containing a filler, and has compatibility with the polypropylene and the core material 1a.
Examples of the thermoplastic elastomer that can be used as 1 include an olefin-based thermoplastic elastomer or a styrene-based thermoplastic elastomer, and in the case of the embodiment,
The core material 11 is formed from an olefin-based thermoplastic elastomer.

Also, the core material 11 has a
A bracket 11a in the shape of a quadrangular cylinder is protruded, and a mounting hole 11b is formed in the bracket 11a to insert and lock the claw 5c of the case 5 of the airbag device 1. The bracket 11a is used to connect the breakable portion 16 and the door portions 17 and 18,
The airbag cover 10 is formed so as to be connected to the case 5 of the airbag device 1 so that the airbag cover 10 can be accurately positioned above the folded airbag 2.

The decorative sheet 12 includes a skin layer 13 made of a soft vinyl chloride / olefin-based thermoplastic elastomer / styrene-based thermoplastic elastomer on the outer surface side, a foam layer 14 disposed on the back side of the skin layer 13, Foam layer 1
And a barrier layer 15 made of an olefin-based thermoplastic elastomer / styrene-based thermoplastic elastomer for protecting the skin layer 13 and the foam layer 14 at the time of injection molding of the core material 11. Beforehand, 3
The layers are configured as an integral sheet.

In the case of the embodiment, the skin layer 13 is formed of soft vinyl chloride, the foam layer 14 is formed of foamed polypropylene, and the barrier layer 15 is formed of the same olefin-based thermoplastic elastomer as the core material 11. I have.
The thickness of the skin layer 13 is 0.5 mm, the thickness of the foam layer 14 is 3.0 mm, and the thickness of the barrier layer 15 is 0.7 mm.

A thin-walled tensile weak portion 61 having a concave portion 61a formed in the core material 11 is formed at the portion of the breakable portion 16 to be a tensile weak portion, and a cutout portion 62a is formed in the barrier layer 15. The formed weakened portion 62 is formed, and the skin layer 13 is stretched from the front surface side to the rear surface side, and the thin portion 63b is disposed at the center to form the curved portion 6 having a substantially V-shaped cross section.
3a, a tensile weak portion 63 is formed.

The curved portion 63a is formed continuously along the "H" shape of the portion 16 to be broken, and the concave portion 61a and the cutout portion 62a are formed along the "H" shape of the portion 16 to be broken. It may be formed continuously or intermittently. In the case of the embodiment, the concave portion 61a and the cutout portion 62a are formed continuously.

The thickness of the thin portion 63b having the minimum thickness in the curved portion 63a is 0.3 mm in the case of the embodiment.

The airbag cover 10 and the instrument panel 8
First, as shown in FIG. 4A, the sheet-like decorative sheet 12 including the part of the decorative sheet 9b is heated and softened by the heater 20, and then the sheet B shown in FIG.
As shown in, vacuum molding is performed by applying to a vacuum molding die 21,
It is shaped into a predetermined shape that can be embedded in the instrument panel 8. At this time, the skin layer 13 is pushed and stretched by the convex portion 21b formed on the mold surface 21a of the vacuum forming die 21, and the skin layer 13 has a curved portion 63a having a thin portion 63b as a tensile weak portion 63. Is formed.

Thereafter, as shown in FIG. 4C, a cutout portion 62a is provided in the barrier layer 15 by using the processing horn 22 of the ultrasonic welder.

Then, the decorative sheet 1 shaped into a predetermined shape is formed in a molding die for injection molding the base material 9a of the instrument panel body 9.
2 and 9 are set to form a base material 9a, and the core material 11 of the airbag cover 10 is set in an injection molding die to form the core material 11.

Next, the concave portion 61a is formed again using the processing horn of the ultrasonic welder, and the mounting hole 1 is formed.
By forming 1b, the instrument panel 8 can be manufactured.

The concave portion 61a is formed by using a processing horn, and a convex portion is provided on the mold surface itself of the molding die of the core material 11, and the concave portion 61a is formed at the same time when the core material 11 is formed at the time of molding. It may be formed.

When forming the cutout portion 62a and the concave portion 61a, the cutout portion 62a and the concave portion 61a are formed by using an ultrasonic welder, a heated cutter, or a cutter using high frequency. May be.

Further, after the instrument panel 8 is manufactured, when it is mounted on a vehicle and then connected to the airbag apparatus 1, the inner panel in the case 5 of the airbag apparatus 1 integrated with each bolt 4b is used. Insert the bracket 11a between the outer panel 5b and the
When the airbag device 1 is connected to the instrument panel 8 and the bracket 7 is fixed to the bolts 4b with the nuts 6 and the other end of the bracket 7 is fixed to a frame (not shown), The airbag device 1 can be mounted on a vehicle by being connected to the instrument panel 8. When the instrument panel 8 is mounted on a vehicle, a predetermined instrument or the like is provided.

At a predetermined time, when the gas is discharged from the inflator 3, the gas flows into the airbag 2 through the gas circulation hole 4a of the diffuser 4, and the airbag 2 pushes up the airbag cover 10. It will be. At that time, the airbag cover 10 is subjected to a tensile load, and in the fragile portion 61 of the core material 11 at the portion 16 to be broken, stress concentration occurs at a portion of the concave portion 61a provided on the back surface side. The material 11 breaks and the decorative sheet 1
In the tensile weak portion 62 of the second barrier layer 15, the cut portion 62a
Is provided and cut off, and in the tensile weak portion 63 of the skin layer 13, a thin portion 63b is formed at the center of the curved portion 63a having a substantially V-shaped cross section, and if a tensile load acts, As the cutout 62a of the barrier layer 15 expands,
Thin portion 63b that changes the cross-sectional shape of skin layer 13
, And as a result, the thin portion 63b breaks,
The breakable portions 16 (tensile weak portions 61, 62, 63) of the core material 11 and the decorative sheet 12 will break, respectively. Therefore, the airbag 2 is provided with the airbag cover 10.
Of the airbag cover 10 and the doors 17 and 18 about the hinge 19 of the airbag cover 10 as a center of rotation.
And project from the instrument panel 8 greatly.
In addition, since the foamed layer 14 has a low tensile strength, the foamed layer 14 is easily broken at a portion where the core material 11 or the like is broken.

As described above, in the airbag cover 10 of the embodiment, even if the decorative sheet 12 includes the three layers of the skin layer 13, the foam layer 14, and the barrier layer 15, the decorative sheet 12 is Barrier layer 15 and skin layer 13 of sheet 12
In addition, since the weakened portions 61, 62, 63 formed thinly or cut off intermittently or continuously, when the tensile force acts when the airbag 2 is inflated, the core material 11 The barrier layer 15 and the skin layer 13 are broken at the tensile weak portions 61, 62, and 63, and the airbag 2 can be largely inflated from the opening generated by the break.

By the way, the tensile weak portion 63 is formed on the skin layer 13.
Even if the barrier layer 15 has a higher tensile strength than the skin layer 13, if the cutout portion 62 a is widened so that the barrier layer 15 is broken, the skin layer 13 is also smoothly broken following the cutout 62 a. . Of course, the skin layer 13
By providing the tensile brittle portion 63, the skin layer 13 can be further smoothened.
Will also break.

In the embodiment, the core material 11 on the back side is used.
Is formed by injection molding from a thermoplastic elastomer heat-fusible with the barrier layer 15, and the decorative sheet 12
Is simply set as an insert in the injection mold of the core material 11, and after the mold is clamped, the thermoplastic elastomer is simply injected into the cavity, and can be easily manufactured without using an adhesive or the like.

And, of course, the skin layer 1 of the decorative sheet 12
3. The foam layer 14 is protected by the barrier layer 15 disposed on the back surface side, and can be prevented from being damaged by heat or pressure during the injection molding of the core material 11. Incidentally, in the embodiment, after providing the cut-out portion 62a in the barrier layer 15,
The core material 11 is formed, and the foam layer 14 and the skin layer 13 are formed.
However, it is considered that the core sheet 11 is damaged by heat or injection pressure at the time of molding. However, since the cutout portion 62a has a reduced width (0.1 to 0.5 mm), the decorative sheet is not used. The foam layer 14 and the skin layer 13 are not damaged so much as to affect the outer surface of the metal layer 12.

Therefore, the airbag cover 10 of the embodiment can be easily manufactured even if the skin layer 13 having a high design effect and good feel is provided on the outer surface, and can be easily manufactured when the airbag 2 is inflated. The airbag 3 can be largely inflated by being smoothly broken.

If the skin layer 13 is also provided with the weakened portion 63, the airbag 2 is more clearly broken when inflated, and the airbag 2 can be inflated smoothly.

Further, the airbag cover 10 can be manufactured only by setting the decorative sheet 12 in the injection molding die of the core material 11 and performing the injection molding. Just by increasing the size of the mold, it can be easily handled and manufactured.

Further, since the core material 11 made of a thermoplastic elastomer is formed by injection molding, the molding cycle is shorter than that of an airbag cover manufactured using a material such as urethane, and the time (about half the time) is obtained. (About 2 minutes).

Further, since the core material 11 is formed of a thermoplastic elastomer which can be thermally fused to the barrier layer 15 of the decorative sheet 12, the bonding strength with the decorative sheet 12 is high,
Decorative sheet 1 together with core 11 when airbag 2 is inflated
Even if 2 is broken, it is possible to prevent the decorative sheet 12 from peeling off the core material 11.

Furthermore, since the core material 11 is formed of a thermoplastic elastomer, it is not necessary to separately embed a rigid member for maintaining the shape as compared with the case where a material such as urethane is used.

Further, in the case of the embodiment, as the decorative sheet 12, the foam layer 14 is provided between the skin layer 13 and the barrier layer 15.
, The feel is further improved.

In the embodiment, the cutout 62a is previously formed in the barrier layer 15 of the decorative sheet 12 before the injection molding of the core 11 for integrating the decorative sheet 12 and the core 11 is shown. However, in addition to the above, the cutout portion 62a provided in the barrier layer 15 is formed by injection molding the core material 11 and forming the decorative sheet 12a.
After forming the concave portion 61a of the core material 11 by using a processing horn of an ultrasonic welder, the concave horn 61a and the cut-out portion 62a are operated by inserting the processing horn or the like deeply. They may be provided at the same time. The airbag cover 30 manufactured by such processing is as shown in FIG. 5. In the core material 11, the weakened portion 61 is configured as the cutout portion 62 b.

Further, in the embodiment, as the tensile weak portion 63 provided on the skin layer 13, the one formed by the curved portion 63 a provided with the thin portion 63 b is shown, but as in the airbag cover 40 shown in FIG. Alternatively, a pinhole or a slit 63c may be provided as the tensile weak portion 63 of the skin layer 13.

As shown in the upper part of FIG. 7, the breakable portions 16 are formed by forming the decorative sheets 12.9b into a predetermined shape by vacuum forming, and then inserting a large number of pins or cutters 24 into predetermined positions. The pinholes or slits 63c are formed intermittently. Next, the sheets 12 and 9b are set in a molding die for injection-molding the base material 9a of the instrument panel body 9 to form the base material 9a. After that, as shown in the middle part of FIG.
Form one. Then, as shown in the lower part of FIG. 7, the cutout portion 61 b is continuously or intermittently formed on the core material 11 and the barrier layer 15 along the scheduled break portion 16 by using the processing horn 25 of the ultrasonic welder. If the 62a is provided, the breakable portion 16 can be formed.

The airbag cover 40 can also provide the same functions and effects as those of the above-described embodiment.

Further, a pinhole or a slit 63c is formed in the skin layer 13 by using a pin or a cutter 24.
Is provided, the airbag cover 50 shown in FIG. 8 may be used.

In the airbag cover 50, a pinhole or a slit 63 c is provided at a predetermined position of the decorative sheet 12 by using a pin or a cutter 24, and then a cutout portion 62 a is provided in the barrier layer 15. A concave portion 61a is provided in the core material 11 by using a processing jig by a mold surface at the time of molding or after the molding of the core material 11, so that the tensile weak portion 61
A breakable portion 16 composed of 62 and 63 is formed, and the same operation and effect as in the above-described embodiment can be obtained.

Further, in the airbag cover 10 according to the embodiment, the case 5 of the airbag device 1 is arranged so that the breakable portion 16 and the doors 17 and 18 can be properly arranged above the folded airbag 2. Bracket 11 to be connected with
Although the case where a is provided on the core material 11 is shown, if the airbag cover is arranged with high accuracy above the airbag 2, the bracket to be connected to the case 5 like the airbag cover 60 shown in FIG. 9. Need not be provided.

Furthermore, in each of the embodiments, the airbag covers 10, 30, 40, 50, and 60 used for the instrument panel 8 have been described. However, the airbag covers may cover airbags of airbag devices other than the instrument panel. The present invention can be applied to door trims, seat backs, steering wheel pads, and the like to be arranged.

[Brief description of the drawings]

FIG. 1 is an enlarged sectional view of an airbag cover according to an embodiment of the present invention.

FIG. 2 is a perspective view of the airbag cover.

FIG. 3 is a cross-sectional view showing a usage mode of the airbag cover.

FIG. 4 is a view showing a manufacturing process of the embodiment.

FIG. 5 is a sectional view showing a modification of the airbag cover of the embodiment.

FIG. 6 is a sectional view showing another modification of the airbag cover of the embodiment.

FIG. 7 is a diagram showing a manufacturing process of the airbag cover shown in FIG.

FIG. 8 is a sectional view showing another modification of the airbag cover of the embodiment.

FIG. 9 is a cross-sectional view illustrating a use mode of an airbag cover according to another embodiment.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 ... Airbag apparatus, 2 ... Airbag, 10.30 / 40/50/60 ... Airbag cover, 11 ... Core material, 12 ... Decorative sheet, 13 ... Skin layer, 14 ... Foam layer, 15 ... Barrier layer, 16: Expected breakage part, 61: Tensile weak part, 61a: Depressed part, 61b: Cut part, 62: Tensile weak part, 62a: Cut part, 63: Tensile weak part, 63a: Curved part, 63b: Thin part, 63c ... Pinhole or slit.

────────────────────────────────────────────────── ─── Continuing from the front page (72) Inventor Tetsuya Fujii 1 Ochiai Nagahata, Kasuga-machi, Nishi-Kasugai-gun, Aichi Prefecture Inside Toyoda Gosei Co., Ltd. No. 1 Toyoda Gosei Co., Ltd. (72) Inventor Chiho Yamazaki Chiba, Kasuga-cho, Nishi-Kasugai-gun, Aichi Prefecture No. 1, Nagahata, Ochiai-go No. 1 Inside Toyoda Gosei Co., Ltd. (56) References JP-A-5-162603 (JP, A) JP-A-1 -195036 (JP, A) JP-A-3-90330 (JP, A) JP-A-3-161313 (JP, A) European Patent Application Publication 724817 (EP, A2) (58) Fields investigated (Int. . ^7, DB name) B60R 21/20 B60R 21/16

Claims (2)

(57) [Claims] 1. A synthetic resin airbag cover that covers an airbag and breaks a portion to be ruptured when the airbag is inflated, the airbag cover being disposed on a front surface side and a back surface side, wherein the decorative sheet is provided. A core material formed by injection molding as an insert, wherein the decorative sheet is arranged on an outer surface, and a skin layer arranged on the back side of the skin layer, and the skin at the time of injection molding of the core material is provided. Tensile from the skin layer for protection of the layer
A thermoplastic layer that has a three-layer structure of a barrier layer having increased strength and a foam layer interposed between the skin layer and the barrier layer, wherein the core material is heat-fusible with the barrier layer. And the breakable portion is formed in the barrier layer and the core material, and the breakable portion is configured such that a tensile weak portion is formed intermittently or continuously. Airbag cover. 2. The airbag cover according to claim 1, wherein the tensile weak portion is also formed on the skin layer as a portion to be broken.