JPH10236260A - Cover body for airbag device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To stably hold the mold of a cover body, to prevent a side wall part on a hinge part side from being cracked at the time of development of a ceiling wall part, and to smoothen the rotation of the neighborhood of the hinge part, in the cover body of an airbag device accommodating the airbag. SOLUTION: A cover body for an airbag device is provided with a ceiling wall part 2, which covers an airbag folded inside, a cylindrical side-wall part 3, which is installed as projected from the rear surface of the ceiling wall part 2 in order to accommodate the airbag, a plurality of plate-like reinforcing parts 5, which connects the rear surface of the outer edge part 4 of the ceiling wall part 2 and the outer peripheral surface of the side wall part 3, and rupture parts 7a, 7b, which are formed in a region surrounded by the side wall part of the ceiling wall part 2 and which rupture at the time of inflation of the airbag. In addition, a buckling part 5, which buckles when it is subjected to the stress coming from the outer edge part 4 or the side wall part 3, is formed on the reinforcing parts 5.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a cover body of an airbag device for accommodating an airbag for protecting an occupant from an impact such as an automobile collision.

[0002]

2. Description of the Related Art Hitherto, an airbag device has been proposed in an automobile or the like to protect an occupant from an impact such as a collision. In general, an airbag device is configured such that an airbag is folded and housed in a box-shaped cover together with a gas generator, and when an impact is caused by a collision of an automobile or the like, gas is ejected from the gas generator to release the airbag. The airbag is rapidly inflated, thereby breaking the ceiling wall of the cover body to discharge the airbag from the inside of the cover body, thereby protecting the occupant from colliding with a steering wheel, a dashboard, or the like.

FIG. 6 is a partial sectional view of a cover body of a conventional airbag device. In FIG. 1, a cover body 11 has a ceiling wall portion 12 and a rectangular cylindrical side wall portion 13 that is mounted to protrude from the back surface of the ceiling wall portion 12. Further, an outer peripheral edge 14 is formed by curving downward so as to cover the side wall 13 from the edge of the ceiling wall 12 and protruding in a curved shape, and an outer peripheral edge 14 for maintaining the shape of the outer peripheral edge 14. Back surface 14a
And a reinforcing portion 15 connecting the outer peripheral surface 13a of the side wall portion 13 with the outer peripheral surface 13a.

In the center of the ceiling wall portion 12, there is formed a thin break groove 17 which breaks when the airbag 16 is inflated. When inflated, the break groove 17 is torn and the ceiling wall 12 is opened upward like a door at the joint with the side wall 13 as a hinge 19, and the airbag 16 is discharged to the outside.

FIG. 7 is a front view showing a state in which an airbag device including a cover body 11 is mounted on a steering wheel body 21 of an automobile. The steering wheel body 21 includes an annular rim 22, a boss 23 located at the center of the rim 22, and a plurality of spokes 24 connecting the rim 22 and the boss 23. 11 are arranged.
The partial cross-sectional view shown in FIG. 6 corresponds to a cross-sectional view taken along line BB of FIG.

[0006]

By the way, in the conventional cover body 11, the ceiling wall portion 12 which is broken and opened when the airbag 16 is inflated, the outer peripheral edge portion 14 is opened when the hinge portion 19 is opened around the center of rotation. The reinforcing portion 15 is deformed toward the side wall portion 13 side.
Is pressed against the side wall 13 side.

For this reason, stress concentration occurs in a part of the side wall portion 13, and when the temperature inside the vehicle is low, the resin material is fragile, so that the side wall portion 13 tends to crack. Therefore, a resin material having a low tendency to become brittle at a low temperature is selected, or the lower end edge 15a of the reinforcing portion 15 is formed as an arc surface to form a R.
(Indicated by a broken line in the figure) has been proposed to reduce the stress concentration on the side wall portion 13 (JP-A-8-268201).

However, in this configuration, the reinforcing portion 15
The lower edge 15a of the lower edge 15a is cut along an arc surface to reduce the reinforcing strength, and when the temperature inside the vehicle is high or when the cover 11 is pressed by an occupant, the outer peripheral edge 14 is easily deformed, Inconveniences such as lack of stability of the molding shape occur.

When the temperature inside the vehicle is low, the rotation of the hinge portion 19 still lacks smoothness. Therefore, in order to rotate the hinge portion 19 smoothly even at low temperatures, it is necessary to devise materials and shapes. Therefore, it is necessary to select a material having excellent low-temperature characteristics, so that there is an inconvenience that the material cost increases.

SUMMARY OF THE INVENTION The present invention has been made to solve such a conventional problem, and stably holds the molding shape of a cover body, and cracks a side wall portion on a hinge portion side when a ceiling wall portion is unfolded. It is an object of the present invention to provide a cover body of an airbag device in which the airbag device is prevented from entering the airbag and the rotation in the vicinity of the hinge portion is smoothed.

[0011]

According to the first aspect of the present invention, a cover body of an airbag device according to the present invention has a ceiling wall for covering an airbag folded inside, and an airbag protruding from a back surface of the ceiling wall for mounting. A cylindrical side wall for storing the bag, a plurality of plate-like reinforcing portions connecting the back surface of the outer peripheral edge of the ceiling wall and the outer peripheral surface of the side wall, and an area surrounded by the side wall of the ceiling wall And a rupture portion formed inside the airbag and ruptured when the airbag is inflated, and a buckling portion is formed in the reinforcing portion to buckle under stress from the outer peripheral edge or the side wall.

According to the present invention, when the airbag is stored, the deformation of the outer peripheral edge portion is suppressed without lowering the reinforcing strength by the reinforcing portion, and the molded shape of the cover body is maintained. The buckling portion absorbs the stress applied to the side wall portion from the outer peripheral edge portion by buckling, thereby preventing the side wall portion from being cracked and smoothing the rotation of the outer peripheral edge portion and the ceiling wall portion.

According to a second aspect of the present invention, there is provided a cover body for an airbag device according to the first aspect, wherein the buckling portion is formed to be thinner than the thickness of the reinforcing portion.

According to the present invention, when the airbag is deployed, the thin buckling portion buckles to absorb the stress applied to the side wall from the outer peripheral edge, thereby preventing the side wall from cracking. At the same time, the rotation of the outer peripheral edge and the ceiling wall is made smooth.

According to a third aspect of the present invention, there is provided a cover body of an airbag device according to the first aspect, wherein the buckling portion is formed to be curved in the buckling direction with respect to the reinforcing portion. is there.

According to the present invention, when the airbag is deployed, the buckling portion, which is formed in a curved shape in the buckling direction in advance, buckles and absorbs the stress applied to the side wall from the outer peripheral edge. In addition to preventing the entrance, the rotation of the outer peripheral edge and the ceiling wall is made smooth.

[0017]

FIG. 1 is an external perspective view showing an embodiment of a cover body of an airbag apparatus according to the present invention, and shows a state where the cover body is viewed obliquely from below. The cover body 1 includes a substantially square flat ceiling wall portion 2 that covers the airbag from above, and a rectangular cylindrical side wall portion 3 that is attached to the back surface of the ceiling wall portion 2 so as to project downward in the drawing. An outer peripheral portion 4 which is curved downward in the figure so as to cover the side wall portion 3 from the edge portion of the ceiling wall portion 2, and an outer peripheral edge for maintaining the curved shape of the outer peripheral portion 4. A substantially triangular plate-like reinforcing portion 5, 6 connecting the back surface 4a of the portion 4 and the outer peripheral surface 3a of the side wall portion 3
And

On the back surface of the ceiling wall 2 of the cover 1, thin break grooves 7a and 7b are formed so as to be easily broken when the airbag is inflated. Break groove 7a
Is formed at the center in the front-rear direction of the ceiling wall portion 2 so as to be long in the left-right direction, and the break groove 7b is formed long along the side wall portion 3 in the front-rear direction. A substantially H-shaped breaking groove is formed by the breaking grooves 7a and 7b.

FIGS. 2A and 2B are enlarged views of the reinforcing portion 5 and its periphery, wherein FIG. 2A is a partial sectional view, and FIG.
FIG. In the reinforcing portion 5, the breaking grooves 7a and 7b are torn,
When the ceiling wall 2 is opened upward, the ceiling wall 2 is a connecting member that connects the side wall 31 on the hinge 8 side, which is the center of rotation, and the outer peripheral edge 4. On the other hand, the reinforcing portion 6 is a connecting member that connects the side wall portion 32 along the breaking groove 7b and the outer peripheral edge portion 4.

The thickness of the inner peripheral portion including the lower edge 5c is larger than the thickness of the outer peripheral portion 5a contacting the rear surface 4a of the outer peripheral edge portion 4 and the outer peripheral portion 5b contacting the outer peripheral surface 3a of the side wall portion 31. Is formed thinly to form the buckling portion 5d.

The buckling portion 5d has such a thickness that it can buckle and absorb the stress when it receives a stress from the side wall portion 31 or the outer peripheral edge portion 4. The reinforcing portion 6 is formed to have a uniform thickness as in the related art because the reinforcing portion 6 does not receive stress from the side wall portion 32 and the outer peripheral edge portion 4 when the ceiling wall portion 2 opens upward.

In this configuration, when the airbag is inflated and the break grooves 7a, 7b of the ceiling wall 2 are torn, FIG.
As shown in the partial sectional view of FIG. 7, the ceiling wall 2 opens upward with the hinge 8 as the center of rotation.

At this time, the outer peripheral edge portion 4 is supported by the intersection 9 between the back surface 4a and the outer peripheral surface 3a of the side wall portion 31 as a fulcrum.
Deform to one side. Then, the reinforcing portion 5 receives stress from the outer peripheral edge portion 4, and the buckling portion 5d buckles to absorb the stress applied to the side wall portion 31 as shown in FIG. This prevents the side wall 31 from being cracked, makes the rotation of the outer peripheral edge 4 and the rotation of the ceiling wall 2 smooth, and allows the airbag to be reliably deployed.

Further, since the buckling portion 5d of the reinforcing portion 5 is formed in a thin shape, when the airbag is inflated and presses the side wall portion 3 from the inside, the buckling portion 5d of the reinforcing portion 5 buckles. As a result, the side wall 31 is deformed outward. For this reason, the breaking groove 7a of the ceiling wall portion 2 is pulled to both sides, so that it is easily broken. This also allows the airbag to be reliably deployed. The manner in which the side wall portion 31 is deformed outward due to the inflation of the airbag is shown by a chain line in the bottom view of FIG.

FIG. 5 is a structural view showing another embodiment of the reinforcing portion 5, and is a sectional view taken along line AA of FIG. 2 (a). In the figure, (a) is formed in a tapered shape without providing a step at the boundary between the thick outer peripheral portion 5a and the thin buckling portion 5d. (B) shows that a step is provided only on one side surface and the other side surface is formed in the same plane, so that the buckling portion 5d is formed.
Is formed in a concave shape. (C) is the buckling part 5
The sectional shape of d is formed stepwise in a crank shape. (D) is different from the other embodiments in that the thickness is uniform,
However, by forming the buckling portion 5d in a curved shape in the buckling direction in advance, it is configured to absorb the stress as in the other embodiments.

[0026]

According to the present invention, when the airbag is housed, the deformation of the outer peripheral portion can be suppressed without lowering the reinforcing strength by the reinforcing portion, and the molded shape of the cover body can be maintained. On the other hand, when the airbag is deployed, the buckling portion of the reinforcing portion is buckled to absorb the stress applied to the side wall portion from the outer peripheral edge portion, thereby preventing the side wall portion from being cracked. The airbag can be reliably deployed by smoothing the movement.

When the airbag is inflated and the side wall portion is pressed from the inside, the buckling portion of the reinforcing portion on the side wall portion side along the breaking groove in the central portion of the ceiling wall portion buckles. Since the side wall portion is deformed outward, the breaking groove is pulled on both sides, so that the breaking groove is easily broken. This also allows the airbag to be reliably deployed.

[Brief description of the drawings]

FIG. 1 is an external perspective view showing an embodiment of a cover body of an airbag device according to the present invention.

FIG. 2A is a partial cross-sectional view showing the vicinity of a reinforcing portion,
(B) is the sectional view on the AA.

FIG. 3A is a partial cross-sectional view illustrating the vicinity of a reinforcing portion when a ceiling wall portion is opened, and FIG. 3B is a lower perspective view illustrating only the reinforcing portion at that time.

FIG. 4 is a bottom view showing a state where a side wall portion is deformed outward.

5 (a) to 5 (d) are cross-sectional views taken along line AA of FIG. 2 (a) showing another embodiment of the reinforcing portion.

FIG. 6 is a partial sectional view of a cover body of a conventional airbag device.

FIG. 7 is a front view showing a state in which the airbag device is arranged on the steering wheel body.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Cover body 2 Ceiling wall part 3,31,32 Side wall part 3a Outer peripheral surface 4 Outer peripheral edge part 4a Back surface 5,6 Reinforcement part 5a, 5b Outer peripheral part 5c Lower edge 5d Buckling part 7a, 7b Breaking groove 8 Hinge part 9 Intersection

Claims (3)

[Claims] 1. A ceiling wall covering an airbag folded inside, a cylindrical side wall protruding from a rear surface of the ceiling wall and mounted to house the airbag, and an outer peripheral edge of the ceiling wall. A plurality of plate-shaped reinforcing portions connecting the back surface of the portion and the outer peripheral surface of the side wall portion; and a breaking portion formed in a region of the ceiling wall portion surrounded by the side wall portion and breaking when the airbag is inflated. And a buckling portion formed on the reinforcing portion to buckle under stress from the outer peripheral edge portion or the side wall portion. 2. The cover body for an airbag device according to claim 1, wherein said buckling portion is formed to be thinner than a thickness of said reinforcing portion. 3. A cover body for an airbag device according to claim 1, wherein said buckling portion is formed to be curved in a buckling direction with respect to said reinforcing portion.