JPH1081184A - Cover for air bag device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent shrinks on the surface of a cover for an air bag device by preventing an increase in resin thickness of its side tear lines and accurately directing its tear along the tear lines. SOLUTION: A cover 10 for an air bag device comprises a cover body 11 and fitting side walls 12, 13, 14 and 15. The cover body 11 is formed at its inner wall with a center tear line 21 crossing the substantial center part thereof, and a first side tear line 22 and a second side tear line 23 which meet the center tear line 21 at both ends thereof at substantial right angles. The cover body 11 is sectioned into a pair of door panels 25 and 26 defined by the first side tear line 22, the center tear line 21 and the second side tear line 23, and a pair of side panels 27 and 28 defined by the first side tear line 22 and the second side tear line 23. The side panels are folded toward the backs of the door panels at least the peripheries of the intersections of the center tear line 21 and the first side tear line 22 and the second side tear line 23.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a cover for use in an airbag device for protecting an occupant in the event of a vehicle collision, and more particularly, to an airbag in which the cover is accurately broken along a tear line when the airbag is deployed. The present invention relates to a cover of a bag device.

[0002]

2. Description of the Related Art In order to protect a vehicle occupant from a secondary collision with a steering wheel, an instrument panel and the like in the event of a collision, an airbag device is mounted on the steering wheel and the instrument panel. Conventionally, as a cover of such an airbag device, a cover described in JP-A-6-336145 is known.

[0003] In the above-mentioned publication, first and second tear lines are provided on the back surface of the cover to rupture the cover when the airbag is deployed. This first
The tear line is a portion where an initial break occurs when the cover is broken, and is provided at the center of the cover so as to extend in the width direction of the vehicle body. The second tear line is a portion that breaks following the break of the first tear line, continues to the first tear line, and extends at both ends of the cover in the vehicle width direction in a direction crossing the vehicle width direction. There is provided. Then, the cover mounting side wall and the second side wall are formed such that the breakage of the cover proceeds continuously from the first tear line to the second tear line without proceeding crossing the second tear line.
The thickness between the first tear line and the second tear line is made larger than the thickness on the center side, or a rib is provided along the outside of the second tear line in the vehicle width direction.

[0004]

SUMMARY OF THE INVENTION
The mounting side wall of the cover and the second side wall are so arranged that the rupture of the cover proceeds continuously from the first tear line to the second tear line.
Since the thickness between the first tear line and the second tear line is formed to be larger than the thickness at the center side of the second tear line, the weight of the entire cover is increased. In addition, by forming the ribs along the outer side of the second tear line in the vehicle width direction, the thickness of the cover partially changes suddenly, and sinks are likely to occur on the synthetic resin cover surface. Had also.

The present invention has been made in view of the above-mentioned problems of the prior art, and has as its object to increase the resin thickness outside the second tear line in the vehicle width direction. In addition, an object of the present invention is to provide a cover of an airbag device in which breakage proceeds accurately along the tear line and sink marks do not occur on the surface of the cover.

[0006]

In order to achieve the above-mentioned object, according to the present invention, there is provided a cover body and a mounting side wall extending from the periphery of the cover body to the rear side. A cover of an airbag device for storing an airbag in an internal space, wherein a center tear line that crosses a substantially central portion of the inner wall surface of the cover body and a crossing portion at both ends of the center tear line are substantially formed. A first side tear line and a second side tear line are formed so as to be orthogonal to each other, and the cover body includes a first side tear line,
A pair of door panels formed by a center tear line and a second side tear line, and a pair of side panels formed by a first side tear line and a second side tear line are divided into a center tear line and a first side. The side panel is formed by bending the side panel to the rear side with respect to the door panel at least at the peripheral edge of the intersection with the part tear line and the second side part tear line.

The cover according to the present invention may be used for an airbag device for a driver seat mounted on a steering wheel, or may be used for an airbag device for a passenger seat or a rear seat mounted on an instrument panel or the like. May be used. Here, the cover is made of a synthetic resin, and may be made of a thermoplastic elastomer. The mounting side wall is for mounting the cover to a housing or the like. By attaching the mounting side wall to the housing or the like of the airbag device, the cover constitutes a lid of the airbag device.

[0008] The center tear line is formed by providing a concave groove at a substantially central portion of the inner wall surface of the cover body toward the opposing mounting side wall. Even if this center tear line is formed linearly at the approximate center of the cover body,
It may be curved. The center tear line is a portion where an initial break occurs in the cover when the airbag is deployed.

The first side tear line and the second side tear line are portions that break following the break of the center tear line. The first side tear line and the second side tear line are recessed in the inner wall surface of the cover body so as to be substantially perpendicular to both ends of the center tear line. It is formed by providing a groove. When the airbag is deployed, the center tear line is first broken, and the groove depth of the center tear line is set to the first side so that the first side tear line and the second side tear line are easily broken following the break. It may be formed deeper than the groove depth of the tear line and the second side tear line.

The cover body includes a center tear line and a first tear line.
At least at the periphery of the intersection with the side tear line and the second side tear line, the side panel is formed by bending to the rear side with respect to the door panel. The breaking energy that has progressed to the intersection with the first side tear line and the second side tear line is vector-dispersed, and the break of the cover does not cross the first side tear line and the second side tear line and proceed. The vehicle will travel along the first side tear line and the second side tear line.

Further, the invention according to claim 2 is characterized in that the side panel is bent substantially to the rear side with respect to the door panel. Thus, the first
Along the side tear line and the second side tear line, substantially the entire side panel is bent rearward with respect to the door panel, so that stress is concentrated on the bent portion and the break is caused on the first side. It occurs exactly along the part tear line and the second side tear line. Further, since the bent portion matches the first side tear line and the second side tear line, sink marks formed on the cover surface are difficult to visually recognize.

Further, according to the third aspect of the present invention, both ends of the first side tear line and the second side tear line are curved from an intersection substantially perpendicular to the center tear line to a corner of the mounting side wall. It is characterized by being formed. This curved shape may be, for example, a flat C-shape. In this way, if the both ends of the first side tear line and the second side tear line are provided over the corners of the mounting side wall, the side panel can be opened in the same manner as the door panel when the airbag is deployed, so that the opening area of the cover is increased. Can be increased.

[0013]

Embodiments of the present invention will be described below with reference to the drawings. 1 is a front view of the cover, FIG. 2 is a rear view of the cover, FIG. 3 is a sectional view taken along line XX of FIG. 1, and FIG. 4 is an enlarged sectional view of a main part of the cover.

Reference numeral 10 denotes a cover constituting a lid of the airbag device. The cover 10 includes a cover main body 11 and mounting side walls 12, 13, 14, and 15, which extend from the periphery of the cover main body 11 to the rear side. Then, the cover body 11 and the mounting side walls 12, 13, 14,
Airbag (not shown) in the space defined by 15
Is stored.

The mounting side walls 12, 13, 14, 15 are for mounting the cover 10 to the housing of the airbag device, and are provided with mounting holes 16, 16,. Is provided. Reference numerals 17, 18, 19, and 20 denote engagement edges formed so as to protrude from the peripheral edge of the cover main body 11 so as to align with the vehicle body attachment portion when the cover 10 is attached to the airbag device.

A center tear line 21 is formed on the inner wall surface of the cover main body 11 at a substantially central portion thereof toward the mounting side walls 13 and 15. This center tear line 2
Reference numeral 1 denotes a portion where an initial break occurs in the cover 10 when the airbag is deployed, and is formed by providing a concave groove on the inner wall surface of the cover body 11. In the illustrated example, the center tear line 21 is linearly formed substantially at the center of the cover main body 11 toward the both mounting side walls 13 and 15, but may be formed to be curved.

At both ends of the center tear line 21, a first side tear line 22 and a second side tear line 23 are formed so as to continue from the center tear line 21 so that the crossing portions are substantially orthogonal. First side tear line 22 and second side tear line 22
The side tear line 23 is a portion that breaks following the break of the center tear line 21 and is formed by providing a concave groove on the inner wall surface of the cover main body 11.

When the airbag is deployed, the center tear line 21 is broken first, and the first side tear line 22 and the second side tear line 23 are easily broken following the break. The groove depth may be formed to be deeper than the groove depth of the first side tear line 22 and the second side tear line 23.

Both ends of the first side tear line 22 are curved from the intersection substantially perpendicular to the center tear line 21 to the respective corners of the mounting side walls 12, 13 and the mounting side walls 13, 14. As shown in FIG. 2, when viewed from the back side of the cover, it has a flat C-shape. Further, both ends of the second side tear line 23 are separated from the crossing portion substantially perpendicular to the center tear line 21 by the two mounting side walls 12,
Over each corner of the mounting wall 15 and the mounting side walls 15 and 14,
As shown in FIG. 2, when viewed from the back side of the cover, it has a flat inverted C-shape.

The ends of the first side tear line 22 and the second side tear line 23 are connected to the mounting side walls 12, 13, 14, 15 respectively.
By providing up to the four corners, the opening area of the cover 10 can be increased when the airbag is deployed.
In order to prevent breakage from spreading to other portions of the cover 10 at both ends of the first side tear line 22 and the second side tear line 23, extended ends 22 a,
23a, and these extended portions 22a, 23a
The surrounding wall 24 may be formed on the inner wall surface of the cover body 11 so as to surround the surroundings.

The cover body 11 is divided into four parts by a center tear line 21, a first side tear line 22, and a second side tear line 23. That is, the first
A pair of door panels 25 and 26 formed between the side tear line 22, the center tear line 21, the second side tear line 23 and each of the mounting side walls 12 and 14, the first side tear line 22 and the second side A pair of side panels 27 and 28 are formed between the part tear line 23 and each of the mounting side walls 13 and 15.

The cover body 11 is provided with a center tear line 2.
1 and first side tear line 22 and second side tear line 2
At least at the periphery of the intersection with the side 3, side panels 27 and 28 are formed so as to bend rearward with respect to the door panels 25 and 26. Thus, the center tear line 21, the first side tear line 22, and the second
At the periphery of the intersection with the side tear line 23, the side panels 27 and 28 are
When it is bent to the rear side, when the airbag is deployed, the first side tear line 22 is broken after the center tear line 21 is broken.
And the breaking energy that has progressed to the intersection with the second side tear line 23 is vector-dispersed, so that the breakage of the cover 10 does not advance while crossing the first side tear line 22 and the second side tear line 23, The fracture proceeds along the side tear line 22 and the second side tear line 23.

The side panels 27 and 28 are
When forming a bend on the back side for 5, 26,
Along the first side tear line 22 and the second side tear line 23, the entire side panels 27 and 28 are
5 and 26 may be formed by bending to the back side.
As described above, when the entire surfaces of the side panels 27 and 28 are bent toward the rear side with respect to the door panels 25 and 26, stress is concentrated on the bent portions, and the breakage occurs in the first side tear line 2.
It occurs exactly along the second and second side tear lines 23.
In addition, since the bent portion matches the first side tear line 22 and the second side tear line 23, sink marks formed on the surface of the cover 10 are difficult to visually recognize.

When the airbag is inflated at the time of a collision of an automobile or the like, the cover main body 11 moves to the center tear line 21.
Rupture occurs in the first side tear line 2
It proceeds to the intersection with the second and second side tear lines 23. And the breaking energy is added to this intersection,
Since the side panels 27 and 28 are bent rearward with respect to the door panels 25 and 26, as shown in FIG. 4, the breaking energy A from the center tear line 21 is reduced at the intersection at the side panels 27 and 28. B propagated to
And the energy C that lifts the side panels 27 and 28
And is divided into In practice, as shown by the solid line in FIG.
Since the side panels 27 and 28 are lifted by the energy C, the side panels 27 and 28 and the door panel 2
5 and 26, the energy B transmitted to the side panels 27 and 28 becomes smaller.

The energy B transmitted from the center tear line 21 to the side panels 27 and 28 at the intersection becomes smaller than the energy A according to the angle α, and the angle α increases with the energy C.
The energy B transmitted to the center tear line 21 is greatly reduced, and the fracture from the center tear line 21 is reduced to the first side tear line 2.
The fracture progresses along the first side tear line 22 and the second side tear line 23 without progressing crossing the second and second side tear lines 23.

When the extended portions 22a and 23a and the surrounding wall 24 are formed at the ends of the first side tear line 22 and the second side tear line 23, stress is dispersed by the extended portions 22a and 23a, and Breaks made along the side tear line 22 and the second side tear line 23 are hard to stop at their ends. Thus, the cover body 11 includes the pair of door panels 25 and 26 and the pair of side panels 27 and
28, and the cover 10 expands outward.

[0027]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The cover body 11 has a thickness of 3 mm for the door panels 25 and 26 and a thickness of 2.5 for the side panels 27 and 28.
mm, the thickness of the center tear line 21 is 0.5 mm, and the thickness of the first side tear line and the second side tear line is 0.5 mm.
7 mm and a bending angle α of 26 degrees, the energy B transmitted to the side panels 27 and 28 is theoretically 90
% Or less. Then, at the time of actual breaking, since the angle α increases due to the action of the energy C described above, the energy B is further reduced.

[0028]

As described above, according to the first aspect of the present invention, the breaking energy transmitted to the side panel is adjusted by adjusting the angle at which the side panel is bent rearward with respect to the door panel. Can be reduced, so that the fracture can be accurately advanced along the tear line without reinforcing the side panel. Further, the thickness of the side panel can be made smaller than in the conventional example.

[0029] According to the second aspect of the present invention, in addition to the first aspect of the present invention, since the bent portion and the first side tear line and the second side tear line coincide with each other, a sink mark formed on the cover surface is formed. It becomes difficult to visually recognize, and becomes preferable in appearance. Also, since the bent portion is formed over substantially the entire length of the first side tear line and the second side tear line, the rigidity of the side tear line portion is higher than that of the conventional one, and the bending fatigue performance of the side tear line is also excellent. It becomes something.

Further, the invention of claim 3 can increase the opening area of the cover when the airbag is deployed, in addition to the invention of claims 1 and 2.

[Brief description of the drawings]

FIG. 1 is a front view of a cover.

FIG. 2 is a rear view of a cover.

FIG. 3 is a sectional view taken along line XX of FIG. 1;

FIG. 4 is an enlarged sectional view of a main part of a cover.

FIG. 5 is an enlarged sectional view of a main part of a cover when receiving an initial gas pressure.

[Explanation of symbols]

 Reference Signs List 10 cover 11 cover body 12, 13, 14, 15 mounting side wall 21 center tear line 22 first side tear line 23 second side tear line 25, 26 door panel 27, 27 side panel

Claims (3)

[Claims] 1. A cover for an airbag device, comprising: a cover main body; and a mounting side wall that is bent and extended from a peripheral edge of the cover main body to a rear side, and stores an airbag in an internal space. On the wall surface, a center tear line that crosses substantially the center portion thereof, and first and second side tear lines that are formed so that the crossing portions are substantially orthogonal at both ends of the center tear line are formed. The cover body includes a pair of door panels formed by a first side tear line, a center tear line, and a second side tear line, and a pair of side panels formed by a first side tear line and a second side tear line. At least at the periphery of the intersection of the center tear line with the first side tear line and the second side tear line,
A cover for an airbag device, wherein a side panel is formed by bending a rear panel with respect to a door panel. 2. The cover for an airbag device according to claim 1, wherein the side panel is bent substantially rearward with respect to the door panel. 3. A structure in which both ends of the first side tear line and the second side tear line are formed to be curved from a crossing portion substantially perpendicular to the center tear line to a corner of the mounting side wall. A cover for the airbag device according to claim 1.