JPH0811663A - Air bag cover - Google Patents

Abstract

PURPOSE:To provide an air bag cover rupturing effectively with appropriate force. CONSTITUTION:Continuous inside grooves 6 are provided in crossings 4 between a front wall 2 and side walls 3 of a box type cover main body 1 which forms a cavity 12 for storing an air bag 11 by the front wall 2 and the side walls 3, rupture weak parts 5 rupturing by expansion of the air bag 11 in the bottom side of the inside grooves 6, and inclined faces for inclining toward outside surface side of the side walls 3 are formed on at least one face of the inside grooves 6.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an air bag cover provided in an automobile or the like.

[0002]

2. Description of the Related Art An air bag device for protecting an occupant of a vehicle from a shock such as a collision covers a folded air bag with a cover and injects gas into the air bag at the time of a collision to inflate the air bag. By breaking the cover during expansion and deploying the airbag to project from the cover, the driver is prevented from colliding with the rim portion of the steering wheel and the front glass, and the shock is absorbed.

An airbag device of this type is known, for example, as disclosed in Japanese Patent Application Laid-Open No. 2-225157, and as shown in FIG. 5, an airbag cover a fixed to a steering wheel or the like is used. A break line d is provided on the front wall b (driver's side) and the side wall c in order to promote breakage of the airbag cover a.

By providing the break line d on the front wall b and the side wall c in this way, as shown in FIG. 6, the opening area e of the airbag cover a when the airbag is deployed can be made large, and It is possible to minimize the appearance of defects on the surface of the airbag cover a due to sink marks caused by the formation of weak portions such as the fracture line d.

[0005]

However, in the above-mentioned conventional structure, the airbag is mainly deployed to the front (driver's side) at the initial stage of inflation, and therefore the force applied to the airbag cover a by this deployment is as shown in FIG. As shown in FIG. 5, the amount becomes larger (r) toward the front and smaller (s) toward the side, and the resultant force t acts diagonally forward. Therefore, in the airbag cover a in which the fracture weak portion f is formed by the outer groove on the cover side wall c as shown in FIG. 7, even if the resultant force t of the airbag deployment acts on the airbag cover a, the lateral force is not enough. The force s hardly contributes to the breakage of the cover, and the force component r to the front is used exclusively.
The airbag cover a is broken only by this. This is a tensile cutting for the weakened fracture portion f, which requires a large tensile force and has a problem that the breaking efficiency is not good.

The present invention solves the above-mentioned conventional problems, and an object of the present invention is to provide an airbag cover that is effectively broken by an appropriate force.

[0007]

In order to achieve this object, an airbag cover according to the present invention has a front wall in a box type cover body in which a cavity for accommodating an airbag is formed by a front wall and a side wall. A continuous inner groove is provided on the inner surface of the intersection of the side wall and the side wall, and a weak rupture portion that breaks due to the deployment of the airbag is formed on the bottom side of the inner groove, and the outer side wall is formed on at least one surface of the inner groove. It has a configuration in which an inclined surface that is inclined toward the front surface side is formed.

Further preferably, an outer groove is formed on the outer surface of the cover body so as to face and adjoin the inner groove, and the surface forming the outer groove corresponds to the inclined surface of the inner groove. It has a configuration in which an inclined surface that is inclined toward the outer surface side of the side wall is formed.

Further, preferably, the inner groove has a depth direction formed toward the outer surface side of the front wall of the cover body.

More preferably, the inner groove is formed such that the depth direction thereof is formed toward the outer surface side of the side wall of the cover body.

[0011]

According to this structure, when the airbag is inflated, the combined force of the deploying force acts intensively on the fracture weak part formed on the bottom side of the inner groove provided at the intersection of the front wall and the side wall of the cover body. As a result, the crack progresses along the direction of the inclined surface that is inclined toward the outer surface side of the side wall of the inner groove, and in combination with the tensile cutting that occurs in the fracture weak portion, the fracture weak portion of the cover body can be reliably and efficiently performed. To break.

[0012]

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

FIG. 1 is a perspective view of an airbag cover fixed to a steering wheel of an automobile, and FIG. 2 is a sectional view thereof. In the figure, 1 is a cover body, 5 is a fragile portion, 6
Is an inner groove, and 10 is an airbag cover.

The airbag cover 10 includes a box-type cover body 1, and the cover body 1 is an airbag 1.
1 is composed of a front wall 2 (driver side) and a side wall 3 which form a cavity 12 for accommodating the air bag 1.
1 is arranged in a folded state and housed in the cover body 1.

In the vicinity of the intersection 4 between the front wall 2 and the side wall 3 of the cover body 1, a fragile fracture portion 5 which is ruptured along with the inflation of the airbag 11 is continuously formed. This fragile weak part 5
Is a thin wall formed between the bottom side of the inner groove 6 formed on the inner surface of the front wall 2 of the cover body 1 and the bottom side of the outer groove 8 formed on the outer surface of the side wall 3 adjacent thereto. It is formed on the partition wall 13. Further, the inner surface of the inner groove 6 is an inclined surface 7 which is inclined toward the outer surface side of the side wall 3 of the cover body, and the surface of the outer groove 8 on the front wall 2 side of the side wall 3 of the cover body 1. The inclined surface 9 is inclined toward the outer surface side.

Next, the operation of the airbag cover 10 will be described.

When the airbag 11 is inflated, its deployment force acts on the inner surface of the front wall 2 and the inner surface of the side wall 3 of the cover body 1 as forces r and s, respectively. By acting on the thin partition wall 13 between the outer groove 8 provided and the inner groove 6 provided on the front wall 2 adjacent thereto, stress concentrates on the partition wall 13 and becomes a breaking stress, and the partition wall 13 is broken. To break.

This rupture proceeds in a state in which both the progress of the crack in the direction p of the inclined surface 7 of the inner groove 6 and the tensile cutting of the thin partition wall 13 are organically combined.
The crack promotes the cutting, and the cutting promotes the crack to proceed.
Therefore, the concentrated stress acting on the partition wall 13 promotes reliable and efficient breakage, and enables the smooth expansion of the cover body 1.

The inner groove 6 of the front wall 2 of the cover body 1
Is formed on the inner surface of the side wall 3 as shown in FIG.
The surface opposite to the front wall 2 may be inclined toward the outer surface side of the side wall 3 of the cover body 1 to form the inclined surface 7. Also in this case, similarly to the above, the synthetic force due to the expansion of the airbag 11 acts on the thin partition wall 13 between the outer groove 8 and the inner groove 6 adjacent thereto, so that the stress is concentrated on this partition wall 13. As a result, a breaking stress is generated and the partition wall 13 is reliably and efficiently broken.

The relationship between the inner groove 6 and the outer groove 8 of the weak break portion 5 of the cover body 1 described above is such that the formation of the inclined surface 7 in the inner groove 6 causes cracks along the direction p of the inclined surface 7. Therefore, at least one of the surfaces forming the inner groove 6 may be inclined toward the outer surface side of the side wall 3. Also, for the same reason, the inclined surface 7 of the inner groove 6
The breakage is more effective when the groove is made to correspond to the inclined surface 9 of the outer groove 8.

However, when the cover body 1 has a structure in which the inclined surface 7 of the inner groove 6 promotes reliable and efficient progress of fracture, the outer groove 8 may not have the inclined surface 9. Further, in some cases, the outer groove 8 itself may not be provided.

[0022]

As described above, the present invention is continuous with the inner surface of the intersection of the front wall and the side wall in the box-type cover body in which the front wall and the side wall form the cavity for accommodating the airbag. An inner groove is provided, a weak rupture portion is formed on the bottom side of the inner groove to break due to the deployment of the airbag, and an inclined surface inclined toward the outer surface side of the side wall is formed on at least one surface of the inner groove. By doing so, when the airbag is inflated, the synthetic force of the deploying force acts intensively on the fragile weak portion formed on the bottom side of the inner groove provided at the intersection of the front wall and the side wall of the cover body, The crack progresses along the direction of the inclined surface that is inclined toward the outer surface side of the side wall of the inner groove, and in combination with the tensile cutting that occurs in the weak fracture portion, the weak fracture portion of the cover body is reliably and efficiently broken. Can achieve an excellent airbag cover

[Brief description of drawings]

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

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

FIG. 3 is an operation explanatory view of the airbag cover.

FIG. 4 is a cross-sectional view of another airbag cover of the present invention.

FIG. 5 is a perspective view of a conventional airbag cover.

FIG. 6 is a perspective view of the airbag cover when it is deployed.

FIG. 7 is a cross-sectional view of a main part of the airbag cover.

[Explanation of symbols]

 1 Cover Main Body 2 Front Wall 3 Side Wall 4 Intersection 5 Weak Weak Section 6 Inner Groove 7 Slope 10 Airbag Cover 11 Airbag

Claims (5)

[Claims] 1. A continuous inner groove is provided on an inner surface of a crossing portion of a front wall and a side wall in a box-type cover body forming a cavity for accommodating an airbag by the front wall and the side wall. An airbag characterized in that a fragile weak portion that ruptures when the airbag is deployed is formed on the bottom side of the side groove, and an inclined surface that is inclined toward the outer surface side of the side wall is formed on at least one surface of the inner groove. cover. 2. The airbag cover according to claim 1, wherein an outer groove is formed on an outer surface of the cover body so as to face and adjoin the inner groove. 3. The airbag cover according to claim 2, wherein an inclined surface that is inclined toward the outer surface side of the side wall is formed on a surface that constitutes the outer groove, corresponding to the inclined surface of the inner groove. 4. The airbag cover according to claim 1, wherein a depth direction of the inner groove is formed toward an outer surface side of a front wall of the cover body. 5. The airbag cover according to claim 1, wherein the depth direction of the inner groove is formed toward the outer surface side of the side wall of the cover body.