JPH08127302A - Air bag unit for automobile - Google Patents

Abstract

PURPOSE: To provide an air bag unit which prevents fixedly-attached leg parts of an air-bag lid from cracking and ensures supporting of the lid by a casing when the lid is opened out. CONSTITUTION: While the fore and hind walls of a casing 1 are cranked in their middle, end parts of fixedly-attached leg parts 4b, 4c projecting from the fore and the hind of the back surface of an air-bag lid 4 are bent in parallel with the cranked parts 1e of the casing and fixed to the bent parts 4e by bolting the two together, and therefore, shearing force hardly acts on the together-bolted parts, these parts are relieved of cracking, and consequently a danger that the air-bag lid 4 springs out, when it is opened out, of an opening of an instrument panel 5 becomes extinct. Workability is remarkably improved because the together-bolted parts are placed in one and the same plane and have all the same installing direction.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an automobile air bag unit mounted on an instrument panel in front of a passenger seat, for example, a casing for preventing cracks from occurring in an air bag grid due to pressure when an air bag is deployed. The present invention relates to an air bag unit having a strong attachment structure for a bag and an air bag grid.

[0002]

2. Description of the Related Art This type of air bag system for an automobile automatically actuates an inflator when an impact greater than a predetermined amount is applied to the automobile, and an air bag installed inside a casing expands the body of an occupant. It protects the driver from danger and is usually installed in the approximate center of the steering wheel to protect the driver. However, the aforementioned danger is greater for passengers in the passenger seat rather than for the driver, so in recent years, the airbag device is often installed in the instrument panel located in front of the passenger seat. .

In the above-mentioned air bag device, for example, an inflator 2 ', an air bag 3', etc. are housed in a casing 1'having an open end as disclosed in Japanese Utility Model Laid-Open No. 4-136974. Same casing 1 '
The open end is covered with an air bag grid 4 ', and a part of the air bag grid 4'is fixed to the casing 1'to form one unit. The airbag unit is fixedly supported via a bracket 7 on a support member 6 installed inside the mounting opening of the instrument panel 5.

However, the mounting structure of the casing 1'and the air bag grid main body 4a 'in the conventional airbag unit, including the unit disclosed in the above publication, projects in parallel from the back surface of the air bag grid main body 4a'. The pair of front and rear fixing legs 4b 'and 4c' are simply fixed along the front and rear outer wall surfaces 1a 'and 1b' of the casing 1'by fixing means 8'such as rivets or screws.

[0005]

By the way, when the airbag 3'is inflated due to the explosion of the inflator 2 ', the airbag bag 4'instantaneously deploys. At the time of this development, a strong internal pressure acts from the inside to the outside on the mounting leg portion 4b 'of the air bag grid 4', and the leg portion is largely deformed. Since all of these strong forces are received by the fixing portion such as the rivet, the leg portion 4b 'may crack at the fixing portion, and the air bag grid 4'may fly out in the direction indicated by the arrow A.

The present invention has been made to solve such a conventional problem, and has a mounting structure for ensuring the support by the casing without cracks in the fixing legs of the lid even when the air bag grid is deployed. An airbag unit having the same is provided.

[0007]

SUMMARY OF THE INVENTION Therefore, according to the present invention, a casing accommodating an air bag, an inflator and the like, a cover for covering an opening of the casing, and front and rear fixing legs fixed to front and rear wall portions of the casing are provided. In an airbag unit attached to a required portion of an instrument panel of an automobile, which comprises an air bag grid made of a synthetic resin, a front and rear wall of the casing is bent inward to form a crank-shaped bent portion, The main constitution is characterized in that the front and rear fixing legs of the grid are bent so as to correspond to the bent portion of the casing, and both are fixed by the co-fastening means at the bent portion.

Further, in the present invention, the front and rear fixing legs of the air bag grid are externally fitted to the front and rear walls of the casing, or are fitted and fixed inside the front and rear walls, preferably corresponding to the bent portion of the casing. The bent portion of the fixed leg portion of the air bag grid is thinly formed.

[0009]

In order to attach the air bag grid to the casing, first, the casing is externally fitted from the opening end side between the front and rear leg portions of the air bag grid, and the bent portion of the leg portion is bent along the bent portion of the casing. Tighten the parts together to secure. The airbag unit of the present invention thus assembled is inserted into the opening of the instrument panel and fixedly supported by the support member via the bracket,
The peripheral portion of the air bag grid body is attached to the opening edge of the instrument panel.

According to the air bag unit of the present invention, the casing and the air bag grid are fastened together by the bent portion of the casing and the bent portion of the air bag grid, which are not directly subjected to the deploying force acting when the lid is deployed. Therefore, almost no shearing force acts on the co-fastened portion, which prevents the occurrence of cracks. In particular, when the bent portion of the bent portion of the air bag grid is made thin, it becomes easy to bend. Further, since the co-fastened portions are all on the same plane and the assembling directions are the same, workability is improved and the number of bolts or rivets can be reduced.

Further, when the above-mentioned fixed leg portion of the air bag grid is fitted between the front and rear walls of the casing and the bent portion is brought into close contact with the inner surface of the bent portion of the casing and both are fastened together at the same portion, the air bag is When the grid is unfolded, the fixed legs of the lid are supported on almost the entire front and rear walls of the casing, which further ensures the prevention of damage to the air bag grid.

[0012]

Embodiments of the present invention will be described below in detail with reference to the drawings. 1 to 3 show an airbag unit which is a typical embodiment of the present invention, and FIG. 1 is a sectional view showing a mounting state of the unit to an instrument panel,
FIG. 2 is a sectional view showing an example of a bent structure of a fixing leg portion of the air bag grid of the unit, and FIG. 3 is an overall configuration diagram of the air bag grid. In these figures, the inflator and the airbag are not shown because they are substantially the same as the conventional ones.

Reference numeral 1 in the drawing is a metal casing having a rectangular horizontal cross section and a bottom surface 1c of a not-shown accommodating portion of the inflator formed in an arc shape, and 4 is externally fitted to the casing 1 from the opening side. It is an air bag grid that closes the opening 1d of the casing 1 leaving a predetermined space, and the air bag grid 4 is made of a synthetic resin molded product. Examples of the synthetic resin material include a urethane-based elastomer, an olefin-based elastomer, a styrene-based elastomer in the case of a single layer, and a urethane-based elastomer in the core layer in the case of a two-layer structure of a core layer and a skin layer. An elastomer, urethane foam for the skin layer, an olefin elastomer for the core layer, and a styrene elastomer for the skin layer can be used.

The feature of the present invention lies in the shapes of the casing 1 and the air bag grid 4. The casing 1 is bent and bent like a crank in the middle portion of the front and rear walls 1a and 1b so that the distance between the front and rear walls 1a and 1b (left and right walls in FIG. 1) is large at the upper part and small at the lower part. The part 1e is formed. A plurality of bolt insertion holes are formed in the bent portion 1e at predetermined intervals along the length direction, and a nut 8 (see FIG. 1) is formed on the back surface of the portion where the bolt insertion holes are formed by welding or the like. It is fixed.

As shown in FIG. 3, one of the air bag grids 4 has a pair of front and rear projections arranged in parallel with each other on the back surface of the flat plate-like main body 4a at intervals closely contacting the upper outer surfaces of the front and rear walls 1a and 1b of the casing 1. It has fixing leg portions 4b and 4c. Further, the starting ends of the fixing leg portions 4b and 4c are connected to each other by the left and right side walls 4d. Further, in the illustrated example, the free ends of the fixing leg portions 4b and 4c can be bent by approximately 90 ° in a direction facing each other by a predetermined dimension. Is configured. In order to make this bending possible, in this embodiment, as shown by the solid line in FIG. 2, the portion along the folding curve is thinly formed, and the protruding length of the fixing leg portions 4b, 4c is set to the above casing. Front and back wall 1
The crank-shaped bent portion 1e formed in a and 1b has a size sufficient for abutting the bent portion 4e in a bent state. The bent portion 4e is also formed with a bolt insertion hole 4f (see FIG. 3) at a portion corresponding to the bolt insertion hole.

In order to attach the air bag grid 4 to the casing 1 having the above structure, first, the front and rear leg portions 4b and 4c of the air bag grid 4 are fitted along the outer surfaces of the front and rear walls 1a and 1b of the casing 1 from the opening end side. The same leg 4b,
The bent portion 4e of 4c is bent along the bent portion 1e of the casing 1, and then the bolt 8a is inserted into each bolt insertion hole, and the nut 8 is screwed into the casing 1 to fix the air bag grid 4 together.

The air bag unit of the present invention thus assembled is inserted into the opening of the instrument panel 5 as shown in FIG. 1, and is fixedly supported by the support member 7 via a bracket (not shown), and the air bag grid main body 4a. The engaging portion formed on the peripheral edge of the instrument panel 5 is attached to the opening edge of the instrument panel 5.

According to the airbag unit of the present invention, the bent portion 1e of the casing 1 and the bent portion of the lid 4 are such that the casing 1 and the air bag grid 4 are not directly subjected to the deploying force acting when deploying the lid. Since they are fastened together with 4e, the shearing force hardly acts on the fastened portion, and cracks do not enter from the bolt insertion holes 4f of the air bag grid 4. In particular, when the bent portion of the bent portion 4e of the air bag grid 4 is made thin,
Ensure ease of bending at that part. Further, since the co-fastened portions are all on the same plane and the assembling directions are the same, workability is improved and the number of bolts or rivets can be reduced.

FIG. 4 shows a second embodiment of the present invention. According to the second embodiment, the fixing legs 4b, 4 of the air bag grid 4 are shown.
c is inserted between the front and rear walls 1a and 1b of the casing 1, the bent portion 4e thereof is brought into close contact with the inner surface of the bent portion 1e of the casing 1, and both are fastened together at the same portion. With this configuration, the fixed leg portions 4b and 4c of the lid 4 are supported on almost the entire front and rear walls of the casing 1 when the air bag grid 4 is deployed, which is further compared with the first embodiment. Make sure to prevent damage.

[0020]

As is apparent from the above description, according to the automobile air bag unit of the present invention, the casing and the air bag grid are attached to the crank without a strong deployment pressure that acts when the lid is deployed. Since it is fixed by co-clamping at the curved part, the shearing force hardly acts on the co-clamping part, cracks do not occur in the co-clamping part of the air bag grid, and the air bag grid opens the instrument panel during deployment. There is no danger of jumping out of it. Further, since the joint fastening portion is the bent portion of the casing and the air bag grid as described above, and the assembling directions are all on the same plane, the workability is remarkably improved and the number of fixed parts is reduced. It becomes possible.

Further, in particular, when the fixed leg portion of the air bag grid is fitted between the front and rear walls of the casing and the bent portion is brought into close contact with the inner surface of the bent portion of the casing and both are fastened together at the same portion, When the air bag grid is deployed, the fixed leg portions of the lid are supported by almost the entire front and rear walls of the casing, and the air bag grid is reliably prevented from being damaged.

[Brief description of drawings]

FIG. 1 is a cross-sectional view showing a fixing mode of a casing and an air bag grid of an airbag unit which is a first embodiment of the present invention.

FIG. 2 is a cross-sectional view showing a shape of a bent portion in a fixed leg portion of the air bag grid.

FIG. 3 is a perspective view showing an overall configuration of the air bag grid.

FIG. 4 is a cross-sectional view showing a manner of fixing the casing and the air bag grid of the airbag unit according to the second embodiment of the present invention.

FIG. 5 is a cross-sectional view showing a fixing mode of a casing and an air bag grid in a conventional airbag unit.

[Explanation of symbols]

 1, 1 'Casing 1a, 1b Front / rear wall 1c Bottom 1d Opening 1e Bent 4 Air bag grid 4a Main body 4b, 4c (Front and rear) fixing legs 4d Left and right side walls 4e Bent 4f Bolt insertion hole

Claims (4)

[Claims] 1. A casing containing an air bag, an inflator, etc., and an air bag grid made of synthetic resin for covering an opening of the casing and having front and rear fixing legs fixed to front and rear wall portions of the casing. In an airbag unit attached to a required portion of an instrument panel of an automobile, the front and rear walls of the casing are bent inward to form a crank-shaped bent portion, and the front and rear fixing legs of the air bag grid are formed in the casing. An air bag unit for an automobile, characterized in that the air bag unit is bent so as to correspond to the bent portion and is fixed at the bent portion by co-fastening means. 2. The automobile airbag unit according to claim 1, wherein the front and rear fixing legs of the air bag grid are fitted onto the front and rear walls of the casing. 3. The airbag unit for an automobile according to claim 1, wherein the front and rear fixing leg portions of the air bag grid are fitted and inserted into front and rear wall portions of the casing. 4. The airbag unit for an automobile according to claim 1, wherein the bent portion of the fixed leg portion of the air bag grid corresponding to the bent portion of the casing is formed thin.