JP2006298311A - Vehicular airbag system and airbag cover - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an airbag cover for preventing a crack or breakage of a cover caused by inflation and development of the airbag and preventing damage of the airbag when the airbag is inflated and developed, and also to provide a vehicular airbag system. <P>SOLUTION: Right and left both ends 38b1, 38c1 and 38b2, 38c2 of a fragile line 38 for cleavage are formed in a circular arc mutually curved outward from both ends of a door hinge parts 223a and 223b. Cuts of the ends 38b1, 38c1 and 38b2, 38c2 are shallower than the cut in the other area of the fragile line 38 excluding the ends. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a vehicle air bag device and an air bag cover that covers the air bag device, and more particularly to an air bag cover having a fragile line for tearing to deploy the air bag and a vehicle air bag device using the air bag cover.

A vehicle airbag device for protecting a passenger in a vehicle such as a passenger seat or a driver's seat from the impact of a collision at the time of a frontal collision or a side collision of a vehicle such as an automobile and ensuring the safety of the passenger is an airbag, An airbag case that accommodates the airbag in a folded state so as to be easily inflated and deployed, and an inflator that inflates the folded airbag in a short time. In particular, the airbag device used for the driver's seat and passenger's seat is installed inside the airbag cover such as the instrument panel cover that constitutes the dashboard, and the inflator is used when the vehicle is suddenly decelerated due to a collision of the vehicle. The air bag is rapidly inflated by the high pressure gas from the inflator and the air bag cover is opened along the fragile line, and at the same time, the air bag is deployed and inflated outside the air bag cover. To protect from.
In addition, the fragile line for cleavage for inflating and deploying the air bag of such a vehicle air bag device to the outside of the air bag cover is obtained by continuously processing dot-like holes on the back surface of the air bag cover by laser cutting. (For example, refer to Patent Document 1).
JP 2005-22453 A

A cover of a conventional vehicle airbag apparatus will be described with reference to the drawings.
An air bag cover 10 shown in FIG. 1 corresponds to an instrument panel cover of a vehicle and is formed into a plate shape having a three-dimensional curved surface by a resin material such as PP (polypropylene resin) or TOP (thermoplastic polyolefin resin). Molded.
As shown in FIG. 2, a fragile line 11 for cleavage for inflating and deploying the airbag to the outside of the airbag cover 10 is formed on the back surface of the airbag cover 10. The fragile line 11 for cleavage is composed of one first cleavage line 11a extending in the lateral direction, and 2 extending in a direction perpendicular to the first cleavage line 11a at both ends of the first cleavage line 11a. The second cleavage line 11b of the book is generally H-shaped in plan view.

Further, a flange portion 13A of a frame body 13 made of PP or TOP having a size surrounding the frangible fragile line 11 is bonded to the back surface of the cover 10 by vibration welding or the like.
In the frame 13, there is a reinforcing member (not shown) made of PP or TOP for reinforcing the mechanical strength of the airbag cover 10 in the region where the first cleavage line 11 a and the second cleavage line 11 b are formed. A part of the reinforcing member is attached to the back surface of the airbag cover 10 in the region by vibration welding or the like. Further, an air bag device including an air bag, an air bag case, and an inflator (not shown) is attached to the frame body 13.

  In such a vehicle air bag device, the impact force when the vehicle collides is detected by a sensor, and a control unit comprising a CPU determines whether or not the detected value of the sensor is equal to or higher than a predetermined set value. When it is determined that the value is greater than or equal to the value, the inflator is operated by a command signal from the control unit to supply high-pressure gas to the airbag, and the airbag is rapidly inflated. When the air bag is inflated, the air bag cover 10 in the region where the fragile line 11 for cleavage is applied is pressed from the back surface by the pressure when the air bag is inflated, so that the region is connected to the first cleavage line 11a and the second cleavage line 11b. Cleaved along. The unfolding door 14 (shown by a two-dot chain line in FIG. 1) generated thereby causes a hinge portion to be located on a line connecting the opposite ends of the second cleavage line 11b positioned on the left and right sides of the first cleavage line 11a. At the same time, the airbag is inflated and deployed to the outside of the airbag cover 10. As a result, the cushioning action of the airbag supports the occupant's head or chest and protects the occupant from the impact force at the time of collision.

Next, another example of the fragile line for cleavage formed on the back surface of the conventional air bag cover will be described with reference to FIG.
In FIG. 3, the fragile line 16 for cleavage formed on the back surface of the airbag cover 10 has one first cleavage line 16 a extending in the lateral direction, and is positioned at both ends of the first cleavage line 16 a. It consists of two second cleavage lines 16b extending in a direction perpendicular to the one cleavage line 16a, and has a substantially H shape in plan view as a whole. Moreover, both ends 16b1 and 16b2 of the second cleavage line 16b are curved in a semicircular shape of 180 degrees toward each other.

Further, still another example of the fragile line for cleavage formed on the back surface of the conventional air bag cover will be described with reference to FIG.
In FIG. 4, the fragile line 17 for cleavage formed on the back surface of the air bag cover 10 includes a first rupture line 17a extending in the lateral direction and both ends of the first rupture line 17a. It consists of two second cleavage lines 17b extending in a direction perpendicular to the one cleavage line 17a, and has a substantially H shape in plan view as a whole. Further, both ends 17b1 and 17b2 of the second cleavage line 17b are curved inwardly into a 90-degree arc shape.
Also in the airbag cover 10 having such a fragile line 16 or 17 for cleavage, the fragile line for cleavage is cleaved similarly to the case of the fragile line 11 for cleavage shown in FIG. It can be expanded and deployed outside.

  However, in the airbag cover 10 having the fragile line 11 for cleavage as shown in FIG. 2, the fragile line 11 for cleavage is cleaved with the expansion of the airbag, and the developing door 14 is indicated by a two-dot chain line in FIG. 1. 1 and 2, cracks 15a extending outward from the corners located at both ends of the hinge portion 15 occur in the airbag cover 10 as shown in FIGS. 1 and 2, and the airbag cover breaks. There was a risk of being.

  Further, in the airbag cover 10 having the fragile lines 16 and 17 for cleavage as shown in FIGS. 3 and 4, both ends 16b1, 16b2, 17b1 and 17b2 of the second cleavage lines 16b and 17b are inwardly halfway 180 degrees. As shown in FIG. 5, the deployment door 18 generated by the tearing along the fragile lines 16, 17 for breaking is formed on the outer side of the airbag cover 10 because it has a circular or 90-degree curved shape. When it is deployed to the projecting portion 18, a semicircular or arcuate projection 19 formed at both ends of the hinge portion 18 a of the deployment door 18 projects into the opening 10 </ b> A generated by the deployment of the deployment door 18. There has been a problem that the airbag that is inflated and deployed is caught and damaged.

  The present invention has been made to solve the above-described conventional problems, and prevents the cover from being cracked and broken due to the expansion and deployment of the airbag, and the airbag during the expansion and deployment of the airbag. It is an object of the present invention to provide a vehicle airbag device that can prevent damage to the vehicle and an airbag cover used in the vehicle airbag device.

  In order to achieve the above object, the present invention provides an air bag cover having a resin panel covering an air bag, wherein the panel body has a development area having an area necessary for inflating and deploying the air bag. In the unfolded region, a fragile line for tearing to form a door that can be double-opened or single-opened is formed by cutting a desired depth from the back surface of the panel body into the thickness direction of the panel body, The hinge portion of the door is located between both ends of the fragile line for cleavage, and both the end regions are formed in an arc shape that curves outward from both ends of the hinge portion. And

  The present invention also provides an air bag, an air bag cover made of a resin panel covering the air bag, and an air that is disposed on the back side of the panel body and is stored in a folded state. A back case, an inflator that inflates and expands the air bag by supplying gas to the air bag, and a back surface of the panel main body so as to surround a periphery of a development area of an area necessary for the air bag inflating and deploying. A vehicle airbag apparatus comprising: a resin frame that supports the airbag case; and a resin reinforcing member that is held by the frame and reinforces the deployment region from the back surface side. Is a position where a fragile line for cleavage for forming a door that can be double-opened or single-opened is inserted in the thickness direction of the panel body from the back surface of the panel body. A hinge formed on the door between the two ends of the fragile line for cleavage is formed by a depth cut, and the two terminal regions are circles that curve outward from both ends of the hinge. It is formed in an arc shape.

  Furthermore, the present invention is stored in an airbag, an airbag cover made of a resin panel covering the airbag, and the airbag disposed on the back side of the panel body in a folded state. An air bag case, an inflator that inflates and expands the air bag by supplying gas to the air bag, and a back surface of the panel main body so as to surround a development area of an area necessary for the air bag inflating and deploying And an air bag device for a vehicle comprising a resin frame that supports the air bag case, wherein the panel is provided with a fragile line for cleavage for forming a door that can be double-opened or single-opened in the unfolded region. Both ends of the fragile line for cleavage formed by a notch of a desired depth inserted in the thickness direction of the panel body from the back surface of the body Hinge of the door is configured to be positioned, end of the both is characterized in that it is formed in an arc shape that is curved outward from both ends of the hinge portion.

  According to the airbag cover of the present invention and the vehicle airbag apparatus using the airbag cover, since both end regions of the fragile line for cleavage are formed in an arc shape that curves outward from both ends of the hinge portion, It is possible to prevent cracks and breakage of the airbag cover due to the opening of the door due to the breakage of the fragile line for cleavage accompanying the expansion and deployment, and to prevent damage to the airbag during the expansion and deployment.

  Further, in the present invention, by making the incision depth of both end regions shallower than the incision depth of other regions of the fragile line for cleavage excluding this end region, cracks and breakage of the air bag cover are surely prevented. it can.

The air bag cover and the vehicle air bag device according to the present embodiment are characterized in that the door hinge portion is positioned between both ends of the fragile line for cleavage, and both the end regions are hinged. It is formed in an arc shape that curves outward from both ends of the part, and the depth of cut of both end regions is made shallower than the depth of cut of other regions of the fragile line for cleavage excluding this end region .
With this configuration, it is possible to prevent cracks and breakage of the air bag cover due to the opening of the door due to the breakage of the fragile line for tearing when the air bag is inflated and deployed, and also prevent damage to the air bag during inflation and deployment. it can.

Hereinafter, an airbag cover and a vehicle airbag apparatus according to Embodiment 1 of the present invention will be described with reference to the drawings.
FIG. 6 is a longitudinal sectional view of a main part showing an example of the case where the airbag cover and the vehicle airbag apparatus using the airbag cover according to the first embodiment are mounted on an instrument panel cover of a vehicle passenger seat, and FIG. FIG. 8 is an enlarged cross-sectional view taken along line 8-8 in FIG. 7, and FIG. 9 is a perspective view showing a state in which the door of the airbag cover in the first embodiment is unfolded. It is.

  In FIG. 6, the vehicle airbag apparatus 100 includes an airbag cover 22 corresponding to an instrument panel cover, an airbag 24, an airbag case 26, an inflator (not shown), a frame body 28, a pair of reinforcing members 30, and the like. .

  The airbag cover 22 includes a resin panel body 221 that is integrally formed of a synthetic resin material such as PP or TOP. The panel body 221 is configured to have a three-dimensional curved surface so as to cover the air bag 24 and cover the surface of an instrument panel core (not shown) made of synthetic resin fixed to a vehicle body (not shown). The instrument panel core is fixed by appropriate means such as a tapping screw.

The airbag 24 is housed in an airbag case 26 made of a metallic plate material in a folded state as shown in FIG.
The frame body 28 is for holding the airbag case 26 and the reinforcing member 30 on the back surface side of the airbag cover 22 as shown in FIGS. 6 and 7, and a reinforcing material such as talc or glass fiber is used for 10-30. It is molded from a polypropylene-based highly elastic resin material mixed in a proportion by weight. The frame 28 has a rectangular tube shape having a cross-sectional area corresponding to a rectangular development region 221A having an area necessary for the inflation and deployment of the airbag 24. Further, a flange portion 281 for bonding is integrally formed of the same resin material as that of the frame body 28 at the edge of the frame body 28 on the panel body 221 side, and the flange portion 281 is vibration welded to the back surface of the panel body 221. It is adhered by means such as.

  As shown in FIGS. 6 and 7, the pair of reinforcing members 30 reinforces the development region 221 </ b> A of the panel body 221 from the back side, and is formed from a synthetic resin material such as PP or TOP. Each reinforcing member 30 is connected to the inner surface of the frame body 28 by a dovetail groove method or the like, and is connected to the upper end of the support piece 301 via a hinge portion 302 so as to be foldable, and in the development region 221A. The reinforcing piece 303 is bonded to the back surface by means such as vibration welding.

  A plurality of hooks 261 are provided on the side plate facing the support piece 301 of the reinforcing member 30 on the upper end opening 26 a side of the airbag case 26. Each of the hooks 261 engages with a hole 301 a provided in the support piece 301 and a hole 261 a provided in the airbag case 26 so as to coincide with the hole 301 a, so that the airbag case 26 can be fixed to the frame body 28. It has become. An inflator accommodating portion 262 that accommodates an inflator (not shown) for supplying inflation gas to the airbag 24 is provided at the lower end portion of the airbag case 26. The airbag case 26 is fixed to a fixing member such as a cross member 34 via a support member 32 by a bolt and nut 36.

As shown in FIG. 7, a fragile line 38 for cleavage is formed in the development region 221 </ b> A of the panel body 221.
The fragile line 38 for cleavage forms doors 222a and 222b (see FIG. 9) that can be double-opened (spreading) in the deployment region 221A when the fragile line 38 for cleavage when the airbag 24 is inflated and deployed. For this purpose, it is formed by cutting a desired depth from the back surface of the panel body 221 in the thickness direction of the panel body 221.
The fragile line for cleavage 38 that forms the doors 222a and 222b that can be opened on both sides includes a first rupture line 38a that extends in the lateral direction at the center of the deployment region 221A, and the first rupture line 38a. It is composed of two second cleavage lines 38b and 38c that are located at both ends and extend in the vertical direction perpendicular to the first cleavage line 38a, and has a substantially H shape in plan view as a whole.

  Further, the doors 222a and 222b are provided between the two left and right ends 38b1 and 38c1 of the two second cleavage lines 38b and 38c, and between the other left and right ends 38b2 and 38c2. Hinge portions 223a and 223b (see FIG. 9) are positioned, and both left and right terminal ends 38b1 and 38c1 and 38b2 and 38c2 are formed in an arc shape that curves outward from both ends of the hinge portions 223a and 223b. Has been.

  Further, as shown in FIG. 7, the flange portion of the frame body 28 adhered to the back surface of the panel body 221 so as to surround the development region 221A along the second cleavage lines 38b and 38c and the hinge portions 223a and 223b. 281 is configured to overlap with the end points 38b1, 38c1 and 38b2, 38c2.

Such a fragile line for cleavage 38 irradiates a pulsed laser beam from the back surface of the panel body 221 to continuously process a small-diameter blind hole 39 that does not penetrate the panel body 221 as shown in FIG. It is formed by. The depth of cut of the end points 38b1, 38c1 and 38b2, 38c2 by this laser cut, that is, the depth of the blind hole 39 is the depth of cut in the other region of the fragile line 38 for cleavage excluding this end, That is, it is processed to be shallower than the depth of the blind hole 39.
In addition, infrared light having a wavelength of 10.6 μm focused to a diameter of 0.2 to 0.5 mm is used for the laser beam for processing the fragile line 38 for cleavage.

  As described above, in the vehicle airbag device 100 of this embodiment, when the vehicle collides, the impact force at the time of the collision is detected by a well-known sensor (not shown), and the impact force detected by this sensor is determined in advance. It is determined by a control device composed of a well-known CPU or the like (not shown) whether or not the value exceeds the specified value. Here, when the sensor determines that the detected value is greater than or equal to the set value, a known inflator (not shown) is operated by a signal output from the control device to generate a predetermined gas, and this gas is supplied to the airbag 24. By supplying, the airbag 24 is rapidly inflated and deployed.

  When the airbag 24 is rapidly inflated and deployed, when the pressure generated at the initial stage of the inflation and deployment is applied to the deployment region 221A via the reinforcing piece 303 of the reinforcing member 30, the deployment region 221A extends along the fragile line 38 for cleavage. At the same time, the doors 222a and 222b are opened to the outside of the panel body 221 in a double-open state as shown in FIG. 9 with the hinges 223a and 223b as fulcrums. At the same time, the airbag 24 is inflated and deployed outside the panel body 221 with the double opening operation of the doors 222a and 222b. Thus, the cushioning action of the airbag 24 supports the occupant's head or chest and protects the occupant from the impact force at the time of collision.

  According to the vehicle airbag apparatus 100 of the first embodiment, the left and right ends 38b1 and 38c1 of the second cleavage lines 38b and 38c of the fragile line 38 for cleavage are opposed to each other and opposed to each other. The hinges 223a and 223b of the doors 222a and 222b are positioned between the other left and right ends 38b2 and 38c2, and the left and right ends 38b1 and 38c1 and 38b2 and 38c2 are both ends of the hinges 223a and 223b. Are formed in a circular arc shape that curves outward from each other, and the cut depths of the end points 38b1, 38c1 and 38b2, 38c2 are processed to be shallower than the cut depths of the other regions of the fragile line 38 for cleavage other than the end points. Since it was made to do, the door by tearing of the weak line 38 for tearing accompanying the expansion | deployment deployment of the airbag 24 22a and 222b can be smoothly developed, and even if the doors 222a and 222b are deployed with the hinges 223a and 223b as fulcrums, the occurrence of cracks and breakage in the air bag cover 22 can be prevented and the conventional manner can be achieved. It is possible to prevent damage to the air bag 24 during inflated and deployed.

  Further, according to the first embodiment, the flange portion 281 of the frame body 28 bonded to the back surface of the panel main body 221 so as to surround the development region 221A overlaps the end portions 38b1, 38c1, 38b2, and 38c2. Since it comprised, even if pressing force acts on the expansion | deployment area | region 221A of the airbag cover 22 from the outer side, the expansion | deployment area | region 221A is not deform | transformed easily, and intensity | strength can be maintained.

Next, Embodiment 2 of the present invention will be described with reference to FIG.
FIG. 10 is a plan view of the airbag cover according to the second embodiment.

The second embodiment is different from the first embodiment in that the door formed in the development region 221A has a single-open structure.
That is, as shown in FIG. 10, in the development region 221 </ b> A of the panel main body 221, a frangible fragile line 40 having a substantially U shape obtained by extending a U character in the horizontal direction is formed. This fragile line for cleavage 40 is for forming a door 42 that can be opened in the developed region 221A in accordance with the cleavage of the fragile line for cleavage 40 when the airbag 24 is inflated and deployed. As in the case of Example 1, it is formed by cutting a desired depth from the back surface of the panel body 221 in the thickness direction of the panel body 221.

  The hinge portion 44 of the door 42 is positioned between the terminal ends 40a1 and 40b1 of the left and right cleavage lines 40a and 40b opposite to each other. Further, the terminal ends 40a1 and 40b1 are formed in an arc shape that curves outward from both ends of the hinge portion 44. Furthermore, the depths of the end points 40a1 and 40b1 are processed to be shallower than the cut depths of the other regions of the crushing weak line 40 excluding the end points.

Further, as shown in FIG. 10, the terminal ends 40a1 and 40b1 of the frangible fragile line 40 overlap each other with the flange portion 281 of the frame body 28 bonded to the back surface of the panel body 221 so as to surround the development region 221A. It is configured as follows.
In FIG. 10, the same components as those in FIG.

  According to the first embodiment as described above, although the door 42 is unfolded by the opening of the fragile line 40 for breaking along with the expansion and deployment of the airbag 24, the operational effect is the same as that of the first embodiment. It is the same.

In addition, the shape pattern of the fragile line for cleavage in the present invention is not limited to the shape shown in the first and second embodiments, and the fragile for cleavage is provided in the development region 221A of the panel body 221 so that the airbag 24 can be inflated and deployed. Any door may be used as long as the door formed by a line can be opened so that it can be double-opened or single-opened.
In addition, the present invention is not limited to the above-described embodiment, and can be implemented in various other forms in specific configurations, functions, and effects without departing from the spirit of the present invention.

Next, Embodiment 3 of the present invention will be described with reference to FIG.
FIG. 11 is a plan view of the airbag cover according to the third embodiment.
The difference from Example 1 in Example 3 is that a resin reinforcing member that reinforces from the back side of the double door 14 of the deployment region 221A of the panel body 221 where the airbag 24 inflates and deploys is further omitted. The thickness of the double door 14 in the development area 221A of the panel main body 221 is slightly thinner than the thickness of the panel main body 221, and the rest of the configuration is the same as in the first embodiment, so the same reference numerals are used. A detailed description thereof will be omitted.
That is, the configuration shown in FIG. 11 is applied to a vehicle type equipped with a small inflator that requires less inflation gas to be supplied to the airbag.

It is a perspective view of the conventional air bag cover. It is a plain view of the conventional airbag cover. It is a plain view which shows the other example of the conventional airbag cover. It is a plain view which shows the other example of the conventional airbag cover. It is explanatory drawing of the conventional airbag cover. It is a longitudinal cross-sectional view of the principal part which shows an example of the airbag cover in Example 1 of this invention, and a vehicle airbag apparatus using the same. It is the top view which looked at FIG. 6 from the arrow 7 direction. It is an expanded sectional view which follows the 8-8 line of FIG. It is a perspective view which shows the state by which the door of the airbag cover in the present Example 1 was expand | deployed. It is a top view of the air bag cover in Example 2 of the present invention. It is a longitudinal cross-sectional view of the principal part which shows an example of the airbag cover in Example 3 of this invention, and a vehicle airbag apparatus using the same.

Explanation of symbols

DESCRIPTION OF SYMBOLS 100 Vehicle air bag apparatus 22 Air bag cover 221 Panel main body 221A Deployment area 222a, 222b Door 223a, 223b Hinge part 24 Air bag 26 Air bag case 28 Frame body 281 Flange part 30 Reinforcement member 38 Fragile line 38a for 1st cleavage Line 38b, 38c Second cleavage line 38b1, 38c1, 38b2, 38c2 Termination 40 Cleavage line 40a1, 40b1 Termination 42 Door 44 Hinge part

Claims (7)

An airbag cover having a resin panel covering the airbag,
The panel body has a development area having an area necessary for inflating and deploying the airbag, and a frangible line for tearing to form a door that can be double-opened or single-opened is formed from the back surface of the panel main body. The panel body is formed by cutting a desired depth in the thickness direction of the panel body, and is configured such that hinge portions of the door are located between both ends of the fragile line for cleavage, and both the ends are the hinges. An air bag cover that is formed in an arc shape that curves outward from both ends of the portion.   The fragile line for cleavage is processed by laser cutting, and the depth of cut at both ends by the laser cut is shallower than the depth of cut at other areas of the fragile line for cleavage except the ends. The airbag cover according to claim 1.   A flange portion of a resin frame having a size that surrounds the periphery of the development region along the fragile line for cleavage and the hinge portion is bonded to the back surface of the panel body, and the flange portion is The air bag cover according to claim 1 or 2, wherein the air bag cover is configured to overlap the both ends. An airbag, an airbag cover made of a resin panel covering the airbag, an airbag case disposed on the back side of the panel body and stored in a folded state; and the air An inflator that inflates and expands the air bag by supplying gas to the back, and supports the air bag case that is fixed to the back surface of the panel body so as to surround the periphery of the expansion area required for the air bag inflating and deploying A vehicle air bag apparatus comprising: a resin frame body, and a resin reinforcement member that is held by the frame body and reinforces the development region from the back side;
A fragile line for cleavage for forming a door that can be double-opened or single-opened is formed in the unfolded region by cutting a desired depth from the back surface of the panel body in the thickness direction of the panel body. The door is configured such that the hinge portion of the door is positioned between both ends of the weak line, and the both ends are formed in an arc shape that curves outward from both ends of the hinge portion. Airbag device for vehicles.   The fragile line for cleavage is processed by laser cutting, and the depth of cut at both ends by the laser cut is shallower than the depth of cut at other areas of the fragile line for cleavage except the ends. The vehicle airbag apparatus according to claim 4.   A flange portion of a resin frame having a size that surrounds the periphery of the development region along the fragile line for cleavage and the hinge portion is bonded to the back surface of the panel body, and the flange portion is 6. The vehicle air bag apparatus according to claim 4, wherein the both end portions overlap each other. An airbag, an airbag cover made of a resin panel covering the airbag, an airbag case disposed on the back side of the panel body and stored in a folded state; and the air An inflator that inflates and expands the air bag by supplying gas to the back, and supports the air bag case that is fixed to the back surface of the panel body so as to surround the periphery of the expansion area required for the air bag inflating and deploying A vehicle air bag device comprising a resin frame body,
A fragile line for cleavage for forming a door that can be double-opened or single-opened is formed in the unfolded region by cutting a desired depth from the back surface of the panel body in the thickness direction of the panel body. The door is configured such that the hinge portion of the door is positioned between both ends of the weak line, and the both ends are formed in an arc shape that curves outward from both ends of the hinge portion. Airbag device for vehicles.