JP2761174B2 - Connection structure of base plate and airbag cover and connection method thereof - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a base plate and air in an airbag device which is mounted in front of a passenger seat of an automobile and which instantaneously expands and deploys when a strong impact is applied to the vehicle to reduce the impact of the occupant. More specifically, the present invention relates to a connection structure between a base plate and an airbag cover, which has a simple structure, can be easily assembled and firmly connected, and enables automation, and a connection method thereof. .

[0002]

2. Description of the Related Art In recent years, in order to ensure the safety of occupants and the like, in addition to a conventional seat belt device, when a large impact is applied to a vehicle, the impact is sensed and gas is introduced into the airbag. 2. Description of the Related Art An airbag device has been put into practical use that instantaneously inflates into a balloon shape and cushions and supports the upper body of an occupant with the airbag, thereby greatly reducing the impact force applied to the human body.

[0003] This type of airbag apparatus comprises a metal base plate 2 for airtightly supporting an airbag 1 made of nylon cloth or the like folded into an appropriate size at the periphery of an opening as shown in FIG. An airbag module 5 containing the airbag 1 and having an airbag cover 4 made of a soft synthetic resin fixed by rivets or the like with a peripheral edge wall 4a externally fitted to the peripheral side wall 2a of the base plate 2 is provided. Have. An inflator (gas generator) 6 is further attached to the opening of the airbag module 5, and is attached to, for example, a boss of a steering wheel in front of a passenger seat.

The airbag 1 is made of a nylon cloth or the like. For example, in the event of a vehicle collision, the inflator 6 is ignited by receiving a signal from a sensor for detecting the impact, and rapidly burning gas is discharged from the airbag 1. And the airbag 1 is instantly inflated. The airbag cover 4 is configured to be partially broken and expandable when the airbag 1 is inflated. When the airbag device operates as described above, the airbag cover 4 applies the inflation pressure of the airbag 1. As a result, the airbag 1 is configured so as to be ruptured and deployed, and expanded so that the airbag 1 jumps outward from the ruptured opening and can be largely inflated.

The above-described airbag module 5 is generally mounted on a steering wheel or the like through the following assembling process. That is, after the airbag 1 is airtightly attached to the periphery of the opening of the base plate 2 and the airbag 1 is folded compactly,
The airbag cover 4 is attached to the base plate 2 so as to accommodate the airbag. The installation of the airbag cover 4
In order to fix the positional relationship between the peripheral side wall portion 2a and the peripheral side wall portion 4a after slightly fitting the peripheral side wall portion 4a of the cover 4 outward to the peripheral side wall portion 2a of the base plate 2 while slightly expanding the same. Temporarily fix by temporary fixing means. Thereafter, the base plate 2 and the airbag cover 4 are firmly fixed to each other with a rivet or the like via the backing plate 7. Next, the inflator 6 is attached to the base plate 2 by appropriate means to form the module 5, and the base plate 2 of the module 5 is attached to a steering wheel (not shown).

Here, when the airbag cover 4 is externally fitted to the base plate 2 and attached, the two are temporarily fixed because the airbag 1 attached to the base plate 2 in a folded state is the airbag cover 4. Is pushed up from the inside, the positional relationship between the base plate 2 and the airbag cover 4 is likely to fluctuate, and this is prevented so that work such as riveting can be performed accurately and reliably.

Conventionally, many improvements have been made. One example is a connection structure between an airbag cover and a base plate disclosed in Japanese Utility Model Laid-Open No. 4-115968. FIG. 10 shows the connection structure. According to FIG. 10, either one of the airbag cover 4 and the base plate 2 is placed on or near a line connecting a plurality of fixing portions such as rivets between the airbag cover 4 and the base plate 2. There is provided an engagement means comprising a projection (4b) protruding from one member toward the other member and an engagement portion (2c) provided on the other member engaging with the projection (4b). doing. When the airbag cover 4 is externally fitted to the base plate 2 and attached thereto, usually, in addition to the engaging means, a contact plate 7 is used in the same manner as in the related art, and the base plate 2, the airbag cover 4 and the contact plate 7 After the user is temporarily stopped, the base plate 2 and the airbag cover 4 are firmly connected and fixed by rivets or the like.

[0008]

However, in the connection structure between the airbag cover and the base plate disclosed in the above publication, the projections are made of a metal material in consideration of automation of the assembly process and press molding. It is desirable that it is not formed on the base plate, but formed on the airbag cover. Therefore, in general, an engaging hole or a concave portion as an engaging means is formed on the base plate, and a projection for engaging with the engaging means is formed at a corresponding inner surface position of the airbag cover.

Furthermore, in the method of connecting the airbag cover and the base plate disclosed in the above-mentioned publication, a large number of rivets are used, so that the number of steps for assembling the airbag and the number of parts are increased, leading to an increase in cost. .

The present invention has been made in view of the above circumstances, and an object of the present invention is to employ a simple mechanism as a means for fixing a base plate and an airbag cover, and to simplify a connecting and fixing step, thereby achieving the same step. Of the airbag cover and the base plate, which can easily respond to the automation of the airbag cover, and which does not require fixing means such as rivets, exhibits a strong fixing function, and secures a large counterforce against the deployment force of the cover. A connection structure and a connection method thereof are provided.

[0011]

That is, the object of the present invention is to provide a connecting structure for fitting the peripheral side wall of the base plate to the inner surface of the peripheral standing wall of the airbag cover, wherein A U-shaped fitting that has a fitting piece that is extended to the edge of the side wall portion and whose tip is bent outwardly of the side wall portion and substantially parallel to the side wall portion, and is fitted to the upright wall portion. comprising a part, Ri engaging portion formed on the vertical wall portion of the air bag cover to the fitting Chakuhen or the side wall portion the name has a fastening means for engaging wear, the U-shaped at the time of connection
The entire shape fitting portion is in close contact with the peripheral standing wall portion by pressing.
Until it is achieved by coupling structure of the base plate and the airbag cover, characterized in Rukoto such being plastically deformed.

The above object is also a connecting method for fitting and fixing a peripheral side wall of a base plate to an inner surface of a peripheral standing wall of an airbag cover, wherein the method is provided to extend to an edge of the side wall of the base plate. A fitting portion having a substantially V-shaped cross section having a fitting piece bent outward at a desired angle with respect to the side wall portion is fitted to the tip of the standing wall portion of the airbag cover, and then the fitting is performed. A base plate, wherein the piece is plastically deformed so as to be in close contact with the outer surface of the standing wall portion, and a fastening means formed on the fitting piece is fixedly fastened to a fastening portion of the standing wall portion of the airbag cover; and This is also achieved by a method of connecting the airbag cover.

[0013]

[Function] To use ordinary steel for the base plate,
The cross section of the fitting portion is formed from the beginning in a substantially U shape in which the fitting piece is parallel to the peripheral side wall portion, and a part of the fitting piece or the peripheral side wall portion is made of a soft rigid resin material. When the engaging means for engaging with the engaging portion formed in advance on the peripheral standing wall portion of the airbag cover is formed, the peripheral standing wall portion of the airbag cover is fitted to the fitting portion of the base plate. At the same time, when the fastening means is fastened to the fastening part, the fastening part made of a soft synthetic resin material is easily damaged by the fastening means made of steel.

Therefore, in the present invention, the fitting piece of the base plate is expanded in advance by the method described in claim 2, and the peripheral edge wall of the airbag cover is fitted to the fitting part having a substantially V-shaped cross section. After that, the fitting piece is plastically deformed to have a substantially U-shaped cross section. At this time, the engaging means formed on the fitting piece and / or the side wall of the base plate is simultaneously engaged with the engaging portion of the airbag cover.

The airbag cover thus connected to the base plate is prevented from moving in parallel with the engagement surface by the engagement with the side wall by the engagement portion, and is fitted with the fitting portion having a U-shaped cross section. Thereby, deformation in the direction perpendicular to the side wall surface is also prevented, and a strong connection is realized.

[0016]

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a perspective view showing a connection structure between a base plate and an airbag cover according to the present invention. FIG. 1 is a longitudinal sectional view showing a connection structure example of an airbag cover and a base plate according to a typical embodiment of the present invention.

The airbag module 15 according to the present embodiment
A base plate 12 fixed to a boss 13 of a steering wheel (not shown) via a mounting bracket (not shown) in the same manner as in the prior art; an airbag cover 14 also serving as a center pad of the steering wheel; The airbag 11 includes an airbag 11 that is folded and housed in a housing space formed by the airbag cover 12 and the airbag cover 14, and an inflator 16.

As shown in FIG. 2, the base plate 12 is formed of a rectangular steel box having a circular opening 12c at the center of the bottom surface, and the open end of the airbag 11 housed in a folded state is the circular opening. The flange 16a of the inflator 16 is fixedly supported on the peripheral portion of the opening 12c and the flange 16a of the inflator 16 is attached to the opening 1
2c. The four peripheral portions of the base plate 12 have side walls 12 each of which is one of the characteristic features of the present invention.
a. Base plate 12 having such a configuration
Is manufactured by pressing a normal steel plate.

It should be noted that in this embodiment, the upper end edge of the side wall 12a of the base plate 12 is bent in a U-shape to form a fitting portion 18. The fitting portion 18a is parallel to the side wall 12a. Is a plurality of engaging projections 1 protruding inward.
8b is formed. This engaging projection 18b
Has a substantially F-shaped cross section tapered toward the fitting port as shown in FIG. 3, or has a U-shaped cross section as shown in FIG. Further, the engaging projection 18b
A portion of the side wall 12a opposed to the
Is formed with an escape hole 12b for loosely fitting.

On the other hand, the airbag cover 14 is made of a soft synthetic resin material and has a substantially rectangular box shape having upright walls 14a at four peripheral edges of a surface portion (not shown).
The upright wall 14a is thicker than other parts and has a predetermined rigidity. The upright wall 14a of the airbag cover 14 fitted to the fitting portion 18 of the base plate 12 is completely provided with the upright wall 14a. An engagement hole 14b is formed at a position opposite to the engagement protrusion 18b when the engagement protrusion 18b is fitted to the engagement portion 18. This engagement hole 14b is desirably rectangular.

The base plate 1 constructed as described above
When the airbag cover 14 is fitted and fixed, the base plate 12 made of a normal steel plate has a large bending rigidity and poor elasticity, so that a soft synthetic resin is attached to the fitting portion 18 bent in a U-shape. When the standing wall 14a of the airbag cover 14 made of a material is simply fitted, the fitting projection 18b of the fitting portion 18 hinders the fitting, and the fitting projection 18b is strongly slid. The contact may cause damage to the standing wall 14a.

Therefore, in the base plate 12 having the connection structure shown in FIG. 1 and made of an inelastic metal material, for example, the fitting portion 18 of the side wall 12a is partially bent as shown in FIG. It is formed in an expanded state in a substantially V-shape. The airbag 11 fixed to the outer peripheral surface of the central opening 12c of the base plate 12 by rivets or the like is compactly folded,
In this state, the airbag 11 is housed inside the airbag cover 14 so that the side wall 1 of the base plate 12
2a is pushed along the inner surface of the standing wall 14a of the airbag cover 14. At the time of this pushing, the V-shaped fitting portion 18 formed on the side wall 12a has its insertion opening expanded as shown in FIG. 3B, so that the upright wall 14a is fitted smoothly.

Next, the fitting portion 18 is pressed from the outside by a pressing means such as a punch or a hammer (not shown) to be plastically deformed, thereby obtaining a U-shaped cross section shown in FIG. When the fitting portion 18 is deformed into a U-shape by an external clamping means (not shown), an engaging projection 18 b protruding from the inner surface of the fitting portion 18.
Are engaged with the engaging holes 14b of the upright wall 14a of the airbag cover 14 and are loosely fitted into the opposite holes 12b of the side wall 12a to obtain the connection structure of the present invention.

According to the thus obtained connection structure of the present invention, the engagement between the engagement projection 18b of the base plate 12 and the engagement hole 14b of the airbag cover 14 is as strong as the connection by rivets. Not only
In addition to this, since the outer surface of the airbag cover 14 is supported by the fitting portion 18 of the base plate 12, the drag when the airbag 11 breaks and deploys due to the pressure at the time of gas inflation is sufficiently exhibited.

Also, the step of connecting the base plate 12 and the airbag cover 14 is performed in two steps: a step of pushing the base plate 12 into the airbag cover 14 and a step of pressing with a hammer while reducing the number of parts such as a large number of rivets. The number of processes is sufficient, and it is easy to realize automatic assembly of the airbag device, and it greatly contributes to cost reduction.

FIGS. 6 to 8 show a connecting structure according to another representative embodiment of the present invention. A point to be noted in this embodiment is that a part of a side wall 112a of a base plate 112 is formed with an engagement hole 112b which is engaged with a columnar projection 114b formed on an upright wall 114a of an airbag cover 114, and has a U-shape. The engaging portion 118 is not provided with an engaging means corresponding to the engaging projection 18b in the above embodiment, and furthermore, the side wall 112a is formed by a plurality of (4)
(5) side wall pieces 1 through notches 112d
12a-1 and 112a-2.
a-1 and 112a-2 slightly facilitate elastic deformation in a direction perpendicular to the side wall surface. Further, in the illustrated example, the left and right ends and the end of the central side wall piece 112a-1 are outwardly bent into a U-shape, and the vertical wall 11 of the airbag cover 114 is bent.
4a, a fitting portion 118 is formed. At the substantially central portion of the side wall portion 112a-2 sandwiched between the side wall portions 112a-1 having the fitting portion 118, an engaging hole 112b is formed. I have.

The airbag cover 114 is made of a synthetic resin material having elasticity similarly to the above embodiment, and its upright wall 114a has the above-mentioned engaging hole 112b when it is fitted into the above-mentioned fitting portion 118 as described above. A columnar projection 114b that engages with the engagement hole 112b protrudes from a portion corresponding to. A part of the surface of the cylindrical projection 114b is tapered 1
14c. An engagement hole 112b formed between the fitting portions 118 at the tip of the base plate 112
The cylindrical projections 114b are guided so as to be easily formed so that the columnar projections 114b are securely engaged with the engagement holes 112b without damaging the same.

In the embodiment shown in FIGS. 9 and 10, in the embodiment shown in FIG. 5, a fitting hole 112b is also formed in the fitting piece 118a of the fitting portion 118, and the corresponding standing wall 114a of the airbag cover 114 is formed. The cylindrical projection 114b protrudes from the outer surface of the airbag cover 114, and the columnar projection 114b is not merely fitted to the standing wall 114a of the airbag cover 114, but the cylindrical projection 114b is fitted to the engaging hole 112b. The upright wall 114a of the airbag cover 114 is engaged and supported by the side walls 112a of the base plate 112 from both the inner and outer surfaces, thereby further strengthening the connection.

As is apparent from the above description, the connection structure between the base plate and the airbag cover according to the present invention can be variously modified. For example, in the embodiment shown in FIG. 1, the engaging projection 18b of the base plate 12 may be a cut-and-raised piece that rises obliquely toward the tip of the side wall 12a in addition to the configuration shown in FIGS. In each embodiment shown in FIG. 9, an engagement hole is formed in place of the columnar projection 114b formed on the upright wall 114a of the airbag cover 114, and the side wall piece 1 of one base plate 112 is formed.
Engagement holes 112b formed in 12a-1, 112a-2
Instead, it is also possible to use a cut-and-raised piece that rises obliquely and engages with the engagement hole.

[0030]

As is apparent from the above description, according to the connection structure between the base plate and the airbag cover in the airbag apparatus of the present invention, a simple mechanism is employed as a means for fixing the baseplate and the airbag cover. At the same time, the number of connecting and fixing steps has been reduced, so that it is possible to easily cope with the automation of the steps.In addition, the number of parts has been reduced by eliminating the fixing means such as rivets, so that a significant reduction in cost has been realized. In addition, a strong fixing function is exhibited, and even if the repulsive force of the folded airbag acts on the base plate,
Strong connection is possible with a small number of steps without going through a temporary fixing step, and productivity is remarkably improved.

[Brief description of the drawings]

FIG. 1 is a longitudinal sectional view of an airbag device showing a connection structure example of a base plate and a cover which is a typical embodiment of the present invention.

FIG. 2 is a partial perspective view of the base plate as viewed from the outside.

FIG. 3 is an enlarged sectional view showing an example of a connection structure between the base plate and a cover.

FIG. 4 is an explanatory view showing a connecting procedure of the base plate and the cover according to the embodiment.

FIG. 5 is an enlarged cross-sectional view showing another example of the connection structure of the base plate and the cover.

FIG. 6 is an exploded perspective view showing an example of a connection structure between a base plate and a cover of an airbag apparatus according to another representative embodiment of the present invention.

FIG. 7 is a perspective view from the inside showing a connected state after the base plate and the cover are assembled.

FIG. 8 is an enlarged cross-sectional view of a connection portion showing the connection state.

FIG. 9 is a partial perspective view of a connection structure example of a base plate and a cover according to still another embodiment of the present invention as viewed from the outside.

FIG. 10 is an enlarged cross-sectional view of a connecting portion showing the connecting state.

FIG. 11 is an exploded perspective view of a conventional airbag module.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 11 Airbag 12, 112 Base plate 12a, 112a Side wall 112a-1, 112a-2 Side wall piece 12b Escape hole 12c Opening 13 Boss 14, 114 Airbag cover 14a, 114a Standing wall 14b Engagement hole 15 Airbag module 16 Inflator 16a Flange Part 18, 118 Fitting part 18a, 118a Fitting piece 18b Engagement projection 112b Engagement hole 112d Notch 112e Side wall piece 114b Columnar projection

Claims (2)

(57) [Claims] 1. A connection structure for fitting and fixing a peripheral side wall of a base plate to an inner surface of a peripheral standing wall of an airbag cover, wherein the connection is extended to an end edge of the side wall of the base plate, and a tip end thereof is provided. It has a fitting piece bent outwardly of the side wall part and substantially parallel to the side wall part, and has a U-shaped fitting part fitted to the upright wall part, and is provided on the fitting piece or the side wall part. Ri Na has a fastening means for the fastening and engaging portion formed on the vertical wall portion of the airbag cover, before the time of connection
The entire U-shaped fitting portion is tightly pressed with the peripheral standing wall portion by pressing.
Connection structure of the base plate and the airbag cover, characterized in Rukoto such are plastically deformed until the wear. 2. A connection method for fitting and fixing a peripheral side wall portion of a base plate to an inner surface of a peripheral standing wall portion of an airbag cover, wherein the peripheral side wall portion is extended to an edge of the side wall portion of the base plate, and is connected to the side wall portion. On the other hand, a fitting portion having a substantially V-shaped cross section having a fitting piece bent outward at a desired angle is fitted to the tip of the upright wall portion of the airbag cover, and then the fitting piece is attached to the airbag cover. A base plate and an airbag cover, wherein the base plate and the airbag cover are plastically deformed so as to be in close contact with the outer surface of the upright wall portion, and the engagement means formed on the fitting piece is engaged and fixed to the engagement portion of the upright wall portion of the airbag cover. Consolidation method.