Method for manufacturing crash pad for vehicle and crash pad manufactured thereby

A method for manufacturing a crash pad for a vehicle, may include (a) preparing a die including an upper die and a lower die for forming a first cavity for a Passenger Air Bag (PAB) door and a second cavity for a crash pad body, between the upper die and the lower die, (b) fixing a skin foam on an upper surface of the lower die, (c) moving the upper die in an upward direction in a predetermined distance and filling the first cavity for the PAB door with a first material and the second cavity for the crash pad body with a second material, (d) moving the upper die in a downward direction to compress the first and second materials against the lower die, while the first and second cavities may be filled with the first material and the second material, and (e) extracting a core of the PAB door and the crash pad body integrally formed with the skin foam from the die.

CROSS-REFERENCE TO RELATED APPLICATION

The present application claims priority to Korean Patent Application No. 10-2010-0123071, filed on Dec. 3, 2010 in the Korean Intellectual Property Office, the entire contents of which is incorporated herein for all purposes by this reference.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to a method for manufacturing a crash pad for a vehicle, and more particularly, to a method for manufacturing a crash pad for a vehicle which can reduce a manufacturing step and prevent deformation of a skin foam by molding a core and the skin foam in an integral body. In addition, the present invention relates to the crash pad for the vehicle manufactured by the above manufacturing method.

2. Description of Related Art

A crash pad for a vehicle is generally manufactured by injection-molding one kind of synthetic resin in a die.

After that, after an airbag is mounted at a passenger side, the crash pad is provided with an airbag tear line, which is machined by laser, at a portion built with a passenger airbag such that the passenger airbag is deployed. Recently, an area, provided with the passenger airbag, including a PAB tear line is made from a high-soft material by dual injection molding which injects two materials at the same time, in order to manufacture a crash pad which can easily open a PAB door.

FIG. 1is a view illustrating a process of adhering a skin foam to a core of a crash pad for a vehicle in the related art after the core is injection-molded by the dual injection molding.FIG. 2Ais a perspective view illustrating the core of the crash pad for the vehicle in the related art, andFIG. 2Bis a view schematically illustrating a filling region of each material forming a crash pad body and the PAB door inFIG. 2A.

A crash pad160for a vehicle in the related art includes a core170having a crash pad body172and a PAB door171, and a skin foam180adhered to a surface of the core170by an adhesive or the like.

The crash pad body172is made from a high-strength polypropylene fiber (PPF) resin, and the PAB door171is made from a thermoplastic olefin (TPO) resin having higher softness than that of the crash pad body172so as to easily deploy the airbag.

The core170is formed by the dual injection molding as shown inFIG. 2, and a process of forming the core will be described in detail. A TPO supply line141and a PPF supply line142connected to an injector are respectively connected to a cavity140afor the PAB door and a cavity150afor the crash pad body, and then the TPO resin and the PPF resin supplied from the injector are filled in the cavity140afor the PAB door and the cavity150afor the crash pad body, thereby completing the molding of the core170.

A skin foam180is adhered to the surface of the dual-injected core170by an adhesive to form the crash pad160.

However, in the case of the crash pad160in the related art, there is a problem in that since there is required for the process of the adhering the skin foam180to the surface of the core170after the core is injection-molded, manufacturing costs are increased.

In addition, there is another problem in that since the direction of the TPO resin filled from the injector to the cavity140afor the PAB door is leaned toward the right side from the left side (refer to the arrow inFIGS. 2A and 2B), the TPO filling region is excessive and is not uniform.

BRIEF SUMMARY

Various aspects of the present invention are directed to providing a method for manufacturing a crash pad for a vehicle, in which since a core and a skin foam are integrally formed, a manufacturing process is reduced and thus manufacturing costs are decreased, and the crash pad manufactured by the same.

Another subject of the present invention is to provide a method for manufacturing a crash pad for a vehicle which can minimize and equalize a material filling region by setting a direction of a material to be filled into a cavity for a PAB door from an injector from a center to an outer side, and the crash pad manufactured by the same.

In an aspect of the present invention, the method for manufacturing a crash pad for a vehicle, may include the steps of (a) preparing a die including an upper die and a lower die for forming a first cavity for a Passenger Air Bag (PAB) door and a second cavity for a crash pad body, between the upper die and the lower die, (b) fixing a skin foam on an upper surface of the lower die, (c) moving the upper die in an upward direction in a predetermined distance and filling the first cavity for the PAB door with a first material and the second cavity for the crash pad body with a second material, in a state in which volumes of the first cavity for the PAB door and the second cavity for the crash pad body may be increased than volumes thereof in the steps of (a) and (b), (d) moving the upper die in a downward direction to compress the first and second materials against the lower die, while the first and second cavities may be filled with the first material and the second material, and (e) extracting a core of the PAB door and the crash pad body integrally formed with the skin foam from the die.

The upper die may include a first upper die portion for the PAB door which may be provided with the first cavity for the PAB door at a lower portion thereof, and a plurality of second upper die portions for the crash pad body, wherein the second upper die portions may be disposed around the first upper die for the PAB door and provided with the second cavity for the crash pad body at a lower portion thereof.

The first upper die portion for the PAB door may be provided with a first material gate at a center thereof, and the first material supplied from an injector may be moved to a center of the first cavity for the PAB door through the first material gate, and then may be moved to an outer side thereof.

The plurality of second upper die portions for the crash pad body may be provided with a second material gate at each center thereof, and the second material supplied from the injector may be moved to the second cavity for the crash pad body through the second material gate.

The first material may be a high-soft thermoplastic olefin (TPO) resin.

The second material may be a polypropylene fiber (PPF) resin.

The skin foam may be a polypropylene resin.

Also, the above-described subjects are achieved by the crash pad for the vehicle manufactured by the above manufacturing method.

With the method for manufacturing the crash pad for the vehicle and the crash pad manufactured by the same according to the present invention as described above, the process is eliminated by molding the core and the skin foam in an integral unit. In addition, after the upper die is moved in the upward direction and then the volumes of the cavity for the PAB door and the cavity for the crash pad body are increased, the cavities are filled with the first material and the second material to inject the core and the skin foam at a low pressure, thereby preventing deformation of the skin foam.

In addition, with the method for manufacturing the crash pad for the vehicle and the crash pad manufactured by the same according to the present invention, since the first material filled into the cavity for the PAB door from the injector is moved from the center to the outer side the filling region of the first material can be minimized and equalized.

DETAILED DESCRIPTION OF THE INVENTION

A die10for manufacturing a crash pad for a vehicle according to an exemplary embodiment of the present invention will now be described with reference toFIGS. 3 to 6.

The die10includes an upper die20and a lower die30. A first cavity40afor a PAB door and a second cavity50afor a crash pad body are formed in a space between the upper die20and the lower die30.

In an exemplary embodiment of the present invention, the die10is configured in such a way that an upper die and a lower die of a conventional die are turned over, that is, the upper die in the related art serves as the lower die30and the lower die in the related art serves as the upper die20. Therefore, a first material gate41which will be described later can be placed at a center of the first cavity40afor the PAB door.

The upper die20includes a first upper die portion40for the PAB door and a plurality of second upper die portions50for the crash pad body which are disposed around the first upper die portion40for the PAB door.

In this instance, the lower portion of the first upper die portion40for the PAB door is provided with the first cavity40afor the PAB door, and the lower portion of the plurality of second upper die portions50for the crash pad body is provided with the second cavity50afor the crash pad body.

The first upper die portion40for the PAB door is provided with a first material gate41at a center thereof, and the plurality of second upper die portions50for the crash pad body is provided with a second material gate52at centers thereof.

The process of manufacturing the crash pad60for the vehicle according to an exemplary embodiment of the present invention will be described in detail.

(1) The die10including the upper die20and the lower die30for forming the first cavity40afor the PAB door and the second cavity50afor the crash pad body is prepared.

(2) As shown inFIG. 3, the skin foam80is fixed on the upper surface of the lower die30.

The skin foam80is integrally formed with the core70, which will be described later, by using a principle of heat fusion in which the skin foam80is heat-fused to the core by using a polypropylene resin of the same series as the material of the crash pad body72, which will be described later, through the entanglement caused by molecular diffusion of an interface.

(3) At an initial step of the resin filling, the upper die20is moved in the upward direction to increase the volumes of the first cavity40afor the PAB door and the second cavity50afor the crash pad body. The reason of moving the upper die20in the upward direction is that the pressure is minimized when the first cavity40afor a PAB door and the second cavity50afor a crash pad body are filled with the first material and the second material, respectively, thereby minimizing the deformation of the skin foam80.

Next, in the state in which the upper die20is moved in the upward direction, as shown inFIG. 4, the first cavity40afor the PAB door and the second cavity50afor the crash pad body are filled with the first material and the second material.

At that time, the first material is a material forming a PAB door71, and is a thermoplastic olefin (TPO) resin of a higher softness than that of the second material so as to easily deploy the airbag. The second material is a material forming a crash pad body72, and is a polypropylene fiber (PPF) resin.

Meanwhile, according to an exemplary embodiment of the present invention, different from the related art in which the first material is supplied from the lateral side of the cavity140afor the PAB door in a biased way, the first material is supplied to the center of the first cavity40afor the PAB door, and then is moved to the outer side (refer to the arrow inFIGS. 7A and 7B), the filling region of the first material can be minimized and equalized.

In addition, as the second material is supplied to the second cavity50afor the crash pad body through the plurality of second material gates52which are dispersed and installed per region, from the injector, the filling rate can be improved even though the injection is performed at a low pressure.

(4) After that, as shown inFIG. 5, the upper die20is moved in the downward direction to compress the upper die, while the cavities are filled with the first material and the second material.

(5) The core70which is integrally formed with the skin foam80through the above steps is extracted from the die10, thereby obtaining the crash pad60, as shown inFIG. 6.

At that time, the crash pad60includes the core70having the crash pad72and the PAB door71which are formed by the dual injection molding, and the skin foam80which is inserted and integrally formed when the core70is injected.

According to an exemplary embodiment of the present invention, the process is eliminated by molding the core70and the skin foam80in an integral unit. In addition, after the upper die20is moved in the upward direction and then the volumes of the first cavity40afor the PAB door and the second cavity50afor the crash pad body are increased, the cavities are filled with the first material and the second material to inject the core and the skin foam at the low pressure, thereby preventing deformation of the skin foam80.

In addition, since the first material filled into the first cavity40afor the PAB door from the injector is moved from the center to the outer side, the filling region of the first material can be minimized and equalized.