Airbag for front passenger seat for vehicle and manufacturing method thereof

An apparatus includes an airbag door that opens during deployment of an airbag, and a crash pad integrally injection-molded with the airbag door. The airbag door may include a tear groove, torn during the deployment of the airbag; a slanted part; and a variable part, a thickness of which varies. The crash pad may include an insertion part which contacts the slanted part of the airbag door to support the airbag door when the airbag door opens. A method includes simultaneously injecting materials of a crash pad and an airbag door with an upper and a lower mold and a slide mold coupled to one another such that the airbag door is integrally injection molded with the crash pad, retreating the molds, and removing the airbag door by moving the slide mold.

CROSS-REFERENCE TO RELATED APPLICATION

This application claims priority to, and the benefit of, Korean Patent Application No. 10-2006-0123069, filed in the Korean Intellectual Property Office on Dec. 6, 2006, the entire contents of which are incorporated herein by reference.

BACKGROUND OF THE INVENTION

(a) Field of the Invention

The present invention relates to an airbag for a front passenger seat for a vehicle and a manufacturing method thereof in which an airbag door is integral with a crash pad.

(b) Description of the Related Art

A conventional airbag for a front passenger seat includes an airbag housing equipped with an airbag within a crash pad, a door plate which is mounted to the crash pad in front of the airbag housing and is provided with a rotation part, a chute for coupling the airbag housing to the crash pad, and an airbag door disposed in front of the crash pad.

To deploy the airbag, pressure is applied to the door plate, and a tear line on the door cover is torn to permit the airbag to deploy therethrough.

In a conventional method for forming the airbag door, the crash pad is formed by injection molding, and after the crash pad is solidified to some degree, the airbag door is formed by injection molding.

Remaining stress in the solidified crash pad may occur at a boundary surface of the airbag door which contacts the crash pad, so whitening and scratching of the material may occur while the airbag door is taken out and cooled. Furthermore, sink marks may be generated due to excessive thickness of the bonding part of the boundary surface.

SUMMARY OF THE INVENTION

An apparatus includes an airbag door that opens during deployment of an airbag, and a crash pad integrally injection-molded with the airbag door. The airbag door may include a tear groove, torn during the deployment of the airbag; a slanted part; and a variable part, a thickness of which varies. The crash pad may include an insertion part which contacts the slanted part of the airbag door to support the airbag door when the airbag door opens. The sectional shape of the tear groove may have a shape ofor “H”. The airbag door may be made of TPO material, and the crash pad may be made of PPF material. Valve gate timing for the injection molding may utilize a temperature sensor.

A method includes simultaneously injecting materials of a crash pad and an airbag door with an upper and a lower mold and a slide mold coupled to one another such that the airbag door is integrally injection molded with the crash pad, retreating the molds, and removing the airbag door by moving the slide mold. The injecting may include regulating a filling speed of the airbag door such that the airbag door material is prevented from extending beyond the region of the airbag door.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

Exemplary embodiments of the present invention will hereinafter be described in detail with reference to the accompanying drawings.

Referring toFIG. 1toFIG. 4C, an airbag for a front passenger seat according to an exemplary embodiment of the present invention is provided with an airbag door100which rotates outwardly during airbag deployment. The airbag door100includes a tear groove110which is torn by deploy pressure of the airbag, a slanted part120at both ends of the airbag door100, and a variable part130, a thickness of which varies with respect to a lower center of an airbag door body. The airbag includes: a chute part140at a lower part of the airbag door100which extends rearward. The chute part140includes a mount hole142connected to an airbag housing. A crash pad200is injection molded integrally with the airbag door100and is provided with an insertion part210which contacts the slanted part120of the airbag door100to support the airbag door100when the airbag door100outwardly rotates.

A sectional shape of the tear groove110of the airbag door100may have a shape ofor “H”.

The airbag door100is made of TPO material so that its performance is reliable over a wide temperature range. The crash pad is made of PPF material and is formed by an injection mold in a shape of an ellipse such that the filling is performed only at a region of the airbag door.

A temperature sensor10is disposed below the airbag door100, to provide precise valve gate timing for the simultaneous injection mold of the airbag door100and the crash pad200.

A manufacturing method of an airbag for a front passenger seat for a vehicle according to an exemplary embodiment of the present invention includes: a material injection step of injecting materials of both the crash pad200and the airbag door100in a state that upper and lower molds2and4and a slide mold5are coupled to one another such that the airbag door100is integrally injection molded with the crash pad200; a mold retreat step of retreating the upper and the lower molds2and4and the slide mold5after the injection step; and an airbag door taking out step of taking out the airbag door100by moving the slide mold5forward after the forming of the airbag door100.

The material injection step further includes a filling speed regulation step of regulating a filling speed to form the airbag door100such that material is prevented from being filled beyond the boundaries of the airbag door100.

In more detail, referring toFIG. 4A, in order to form the airbag door100on the crash pad200, the upper and the lower molds2and4are coupled to one another as shown in the drawing. At the material injection step, materials are simultaneously injected to the airbag door100and the crash pad200by separate injectors (not shown).

Referring toFIG. 4B, in order to integrally form the airbag door100and the crash pad200which are made of different materials, temperature information detected by the temperature sensor10is input to a valve gate controller20. The valve gate controller20controls valve timing such that material fills the necessary regions.

That is, the region of the airbag door100is filled with TPO material, and the region of the crash pad200is simultaneously filled with PPF material.

Referring toFIG. 3, when the TPO material is filled through a valve gate to the airbag door100, the material filling speeds are set in the sequence of directions of c>b>a.

Referring toFIG. 4C, after the injection of materials to the airbag door100and the crash pad200is completed, the slide mold5moves forward so the airbag door100can be removed in a state that all the upper and the lower molds2and4and the slide mold5are retreated, at step ST300.

Operation of an airbag door of an airbag of a front passenger seat according to an exemplary embodiment of the present invention will be explained.

Referring toFIG. 1andFIG. 2, the airbag door100according to an exemplary embodiment of the present invention is provided with the variable part130, the thickness of which varies with respect to a lower center of an airbag door body. As shown in the cross-sectional view taken along line A-A, the airbag door100has a thickness a at a center thereof and a thickness b at both sides thereof, where b<a.

In addition, the thickness profile shown in the cross-sectional view taken along line B-B is identical to that shown in the cross-sectional view taken along line A-A. In the cross-sectional view taken along line C-C, the thickness is a.

Referring toFIG. 3, the airbag door100is formed by an injection mold with the material filling speeds in sequence of directions of c>b>a. Since the injection mold has different thicknesses as described above, the injection mold of the airbag door100is performed in a shape of an ellipse. If the airbag door100is formed in the method as described above, the stiffness of the airbag door100is enhanced, and at the same time the TPO material is injected only to the region of the airbag door100.

An operation of an airbag door of an airbag of a front passenger seat is as follows: the airbag is deployed toward a front direction of an airbag housing by an inflator (not shown) at a lower part of the airbag door100.

While the tear groove110is torn by the expansion force, the airbag door100is deployed into the cabin, and the slanted part120of the airbag door100serves the role of a hinge of the airbag door100.

Since the airbag door100is completely rotated by the expansion force of the airbag, the airbag door100is not torn so that an occupant of the front passenger seat is prevented from being injured by broken pieces of the crash pad200or the airbag door100and can be safely protected from impact of a vehicle crash.

As described above, in an airbag for a front passenger seat for a vehicle and a manufacturing method thereof according to the present invention, since the crash pad and the airbag door are integral to one another, material joining force is excellent, and the remaining stress at the coupling surface where the crash pad and the airbag door meet does not occur so that whitening and scratch do not occur.

Furthermore, the crash pad and the airbag door are simultaneously injection molded, so manufacture time is reduced.