Abstract:
Disclosed herein is a crash pad for an automotive interior, including a passenger air-bag door, which may have a main resin layer including a door region having a hinge portion and a tear line for a deployment of an air-bag and a crash pad region at least partially surrounding the door region, in which the hinge portion has a groove formed on a lower surface of the main resin layer along a longitudinal direction of the passenger air-bag door, and a lower resin layer disposed on a lower surface of the main resin layer to cover the hinge portion and having flexibility or a percentage of elongation superior to the main resin layer.

Description:
CROSS-REFERENCE TO RELATED APPLICATION 
     The present application claims priority to Korean Patent Application Number 10-2008-0098582 filed on Oct. 8, 2008, the entire contents of which application is incorporated herein for all purposes by this reference. 
     BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     The present invention relates to a crash pad for an automotive interior and an apparatus for manufacturing the crash pad, and, more particularly, to a crash pad for an automotive interior which is adapted to prevent a hinge portion of an air-bag door for a passenger seat from being broken at the time of deployment of a passenger air-bag and an apparatus for manufacturing the crash pad. 
     2. Description of Related Art 
     A crash pad is a panel made of resin material for finishing a front area of a vehicle interior. For a vehicle equipped with a passenger air-bag, the crash pad is provided with a passenger air-bag door to allow the passenger air-bag to be deployed therethrough. 
     As shown in  FIG. 1 , as a rule, the air-bag door  2  is configured such that an area thereof is defined by a tear line  3  and a hinge portion  4  which are formed on the crash pad  1 . When the tear line  3  of the air-bag door  2  is torn and the passenger air-bag door  2  is pushed out by the passenger air-bag at the time of deployment of the air-bag, the hinge portion  2  may break and the door  2  may separate from the crash pad  1  due to a momentarily strong expansionary force of the air-bag. 
     The hinge portion refers to a connecting or boundary region between the door pushed out by the air-bag and the crash pad. The fact itself that the door separates from the crash pad toward a passenger during the deployment thereof may give rise to a consumer&#39;s complaint, and thus initial deployment of the air-bag into a predetermined normal shape cannot be achieved at all. Furthermore, the opening of the crash pad, resulting from the separation of the air-bag door, may disfigure the appearance of the crash pad, and the passenger may be injured by sharp edges (the tear line or the hinge portion) of the air-bag door separated from the crash pad. 
     The information disclosed in this Background of the Invention section is only for enhancement of understanding of the general background of the invention and should not be taken as an acknowledgement or any form of suggestion that this information forms the prior art already known to a person skilled in the art. 
     BRIEF SUMMARY OF THE INVENTION 
     Various aspects of the present invention are directed to provide a crash pad for automotive interior which is adapted to prevent an air-bag door from breaking and then separating from the crash pad at the time of deployment of the air-bag, and an apparatus for manufacturing the crash pad. 
     In an aspect of the present invention, a crash pad for an automotive interior, including a passenger air-bag door, may have a main resin layer including a door region having a hinge portion and a tear line for a deployment of an air-bag and a crash pad region at least partially surrounding the door region, in which the hinge portion has a groove formed on a lower surface of the main resin layer along a longitudinal direction of the passenger air-bag door, and a lower resin layer disposed on a lower surface of the main resin layer to cover the hinge portion and having flexibility or a percentage of elongation superior to the main resin layer. 
     An airbag housing may be disposed under the main resin layer and encloses the hinge portion and the tear line. 
     A transverse section of the groove may have an upwardly-concave shape with a predetermined curvature. 
     The hinge portion may be aligned substantially in parallel to the tear line disposed in the longitudinal direction of the passenger air-bag door. 
     The groove of the hinge portion may include at least a corrugation formed in a traverse direction of the passenger air-bag door, and the lower resin layer includes a bending portion having a shape corresponding to the corrugation of the hinge portion. 
     In another aspect of the present invention, the crash pad for an automotive interior may further include an upper resin layer disposed on an upper surface of the main resin layer to cover the hinge portion and/or the tear line, and having a flexibility or a percentage of elongation superior to the main resin layer. 
     The upper and lower resin layers may be made of the same resin having a flexibility or a percentage of elongation superior to the main resin layer. 
     The upper and lower resin layers may be made of thermoplastic olefin (TPO). 
     The main resin layer may be made of polypropylene filled (PPF) resin. 
     The main resin layer may include a slit having a width between approximately 1 mm and approximately 2 mm on a boundary between the door region and the crash pad region so as to prevent the upper resin layer from propagating to the crash pad region from the door region during formation of the upper resin layer. 
     In further another aspect of the present invention, an apparatus for manufacturing a crash pad for an automotive interior, including a passenger air-bag door, may include an upper mold including an upper recess, a lower mold including a lower recess and matched with the upper mold to define a space enclosed by the upper and lower recesses, an upper core disposed in the upper recess of the upper mold to be slidable up and down therein, a lower core disposed in the lower recess of the lower mold to be slidable up and down therein, and including a convex portion for formation of a hinge portion of a passenger air-bag door, in which the convex portion includes thereon at least a corrugation arranged in a width direction of the lower core, first and second supply lines connected to the upper recess at different positions, and a third supply line connected to the lower recess. 
     A first resin may be injected through the first supply line, and, after completion of the supply of the first resin, a second resin having a flexibility or a percentage of elongation superior to the first resin may be injected through the second and third supply lines simultaneously. 
     The lower mold may include on an upper surface thereof a wedge protruding towards the upper core by a predetermined length for forming a tear line of the passenger air-bag door. 
     The upper recess may include a first cavity and a second cavity having a depth deeper than the first cavity, and the upper core is disposed in the second cavity and has a protruding dam formed along an edge of a lower surface thereof. 
     The methods and apparatuses of the present invention have other features and advantages which will be apparent from or are set forth in more detail in the accompanying drawings, which are incorporated herein, and the following Detailed Description of the Invention, which together serve to explain certain principles of the present invention. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a schematic perspective view showing a conventional crash pad including a passenger air-bag door. 
         FIG. 2  is a cross-sectional view of an exemplary crash pad according to the present invention. 
         FIGS. 3A to 3C  are cross-sectional views showing a configuration for preventing a door hinge portion of the crash pad shown in  FIG. 2  from being broken at the time of deployment of an air-bag, in which  FIG. 3A  represents a state before the deployment of the air-bag,  FIG. 3B  represents an initial state of the deployment of the air-bag, and  FIG. 3C  represents a state of the complete deployment of the air-bag. 
         FIG. 4  is a cross-sectional view of an exemplary apparatus for the crash pad according to the present invention, in which upper and lower cores are omitted for the sake of explanation. 
         FIG. 5  is a cross-sectional view of the apparatus for the crash pad shown in  FIG. 4 , in which the upper and lower cores are disposed in upper and lower mold, respectively. 
         FIGS. 6 to 8  are cross-sectional views showing a process of manufacturing the crash pad using the apparatus shown in  FIG. 5 , in which  FIG. 6  represents formation of a main resin (PPF) layer,  FIGS. 7 and 8  represent formations of upper and lower resin (TPO) layers. 
         FIG. 9  is a cross-sectional view showing functions of a dam formed on the upper core in the formation of the upper resin layer shown in  FIG. 8 . 
     
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
     Reference will now be made in detail to various embodiments of the present invention(s), examples of which are illustrated in the accompanying drawings and described below. While the invention(s) will be described in conjunction with exemplary embodiments, it will be understood that present description is not intended to limit the invention(s) to those exemplary embodiments. On the contrary, the invention(s) is/are intended to cover not only the exemplary embodiments, but also various alternatives, modifications, equivalents and other embodiments, which may be included within the spirit and scope of the invention as defined by the appended claims. 
     Referring first to  FIGS. 2 to 3C , a crash pad according to an exemplary embodiment of the present invention is described. 
     As shown in  FIG. 2 , the crash pad  100  according to various embodiments of the present invention comprises a main resin layer  110  made of polypropylene filled (PPF) resin, and upper and lower resin layers  120 ,  130  made of thermoplastic olefin (TPO) resin that is more flexible than the PPF resin. The PPF resin is a combination of polypropylene resin and filler added thereto, for example talc-filled polypropylene resin. 
     The crash pad  100  is integrally molded through a so-called over-molding process, in which the upper resin layer  120  may be an optional element. 
     The main resin layer  110  may be divided into a door region  100   a  which is defined by a hinge portion  111  and a tear line  112 , and a crash pad region  100   b  positioned around the door region  100   a . In various embodiments, although the door region  100   a  and the crash pad region  100   b  are made of the same resin (PPF), both the regions may also be made of different resins. 
     In various embodiments of the present invention, the hinge portion  111  is configured such that a recess is longitudinally formed along the lower surface of the main resin layer  110 . Specifically, a transverse section of the hinge portion  111  has a gently curved arched shape with a predetermined curvature so that stress is not concentrated to bottom portion of the hinge portion  111 . The hinge portion  111  is provided on a lower surface with corrugations  111   a  formed along the width of the hinge portion, in which the respective corrugations  111   a  extend in a longitudinal direction of the hinge portion. The tear line  112  is formed on a lower surface of the main resin layer  110  to exhibit a neat appearance. Of course, the invisible tear line may be formed on another area on the main resin layer  110 , and may be formed even after molding of the crash pad  100 . 
     In other embodiments of the present invention, the hinge portion  111  has a predetermined thickness without corrugations. The thickness of lower resin layer  130  is configured sufficient enough to extend with elasticity as the main resin layer  110  is bent 
     In various embodiments of the present invention, the upper resin layer  120  is provided on an upper surface of the main resin layer  110  to cover the door region  100   a . The upper resin layer  120  not only improves appearance and tactile sense of the crash pad  100  but also increases a rupture strength of the hinge portion  111  in conjunction with the lower resin layer  130 . Meanwhile, a slit  113  having a width of 1-1.5 mm is formed along a boundary area between the door region  100   a  and the crash pad region  100   b  of the main resin layer  110  in order to prevent the upper resin  120  from propagating to the crash pad region  100   b  from the door region  100   a  during a molding operation of the upper resin layer  120  (an injection molding of TPO resin) and to ensure a neat boundary line between the door region  100   a  and the crash pad region  100   b.    
     The lower resin layer  130  is provided on a lower surface of the main resin layer  110  to cover the hinge portion  111 . The lower resin layer  130  includes a bending portion  131  having a corrugated shape corresponding to the corrugations  111   a  of the hinge portion  111 . The bending portion  131  includes corrugations formed in a thickness direction such that the upper corrugated surface of the bending portion  131  is in close contact with the corrugations  111   a  of the hinge portion  111  and the lower corrugated surface of the bending portion  131  is configured to correspond to the upper corrugated surface. As a result, the bending portion  131  exhibits excellent flexibility. 
     Referring to  FIGS. 3A to 3C , an effect of reinforcing rigidity of the hinge portion  111  of the crash pad  100  is described. 
     As shown in  FIG. 3A , in the case of crash pad  100  mounted on an automobile, a chute  220  of an air-bag module is fused to a back side of the door region  100   a , i.e., a back side of a passenger air-bag door. The chute  220  is assembled with a housing  210  which accommodates a folded air-bag  200  therein. 
     As shown in  FIGS. 3B and 3C , upon deployment of the passenger air-bag, the air-bag  200  breaks the tear line  112  with the aid of a gas pressure from an inflator. At the same time, the air-bag  200  pushes out the passenger air-bag door and expands towards the passenger. At this point, the bending portion  131  covering the hinge portion  111  is stretched thus increasing tension strength of the hinge portion  111  whereas the upper resin layer  120  is compressed with restoring force and thus a bending angle or a radius of curvature on a back side of the hinge portion  111  is increased thus mitigating the stress concentrated on the hinge portion  111 . In this regard, since the surface of the hinge portion  111  and the bending portion  131  of the lower resin layer  130  are provided with corrugations, respectively, distensibility of the area is excellent. Furthermore, since a contact area between the hinge portion  111  and the lower resin layer  130  is increased due to the corrugations, separation of the hinge portion  111  from the main resin layer  110  is prevented even if the hinge portion  111  is broken at the time of deployment of the air-bag is efficiently avoided. 
     In embodiments that the hinge portion  111  has a predetermined thickness without corrugations, the lower resin layer  130  may extend with elasticity as the main resin layer  110  is bent so that separation of the hinge portion  111  from the main resin layer  110  is prevented. 
     Referring to  FIGS. 4 and 5 , an apparatus for manufacturing the above-described crash pad is now described. 
     The apparatus comprises a mold and a resin supply unit. The mold comprises upper and lower mold  10 ,  20 , and upper and lower cores  30 ,  40  which are disposed in the upper and lower mold  10 ,  20 , respectively. The resin supply unit comprises first and second resin supply portions  50 ,  60 , and first to third supply lines  51 ,  61 ,  62 . 
     The upper mold part  10  includes an upper recess  11  at a lower side, in which the upper recess  11  comprises a first cavity  11   a  and a second cavity  11   b  having a depth deeper than the first cavity  11   a . The lower mold part  20  includes a lower recess  21  at an upper side. The upper and lower mold  10 ,  20  are matched with each other so that an enclosed space is defined by the upper and lower recesses  11 ,  12 . Furthermore, the lower mold part  20  includes a wedge  23  protruding from the upper surface thereof to provide a back side of the passenger air-bag door with the tear line  112  (see  FIG. 2 ). 
     The upper core  30  is disposed in the second cavity  11   b  of the upper mold part  10  to be slidable up and down. The upper core  30  includes a dam  31 , which protrudes and is positioned along an edge of the lower surface of the upper core  30  facing the lower mold part  20 . The lower core  40  is disposed in the lower recess  21  of the lower mold  20  to be slidable up and down. The lower core  40  is provided at an upper surface facing the upper mold part  10  with a convex portion  41  having a predetermined length so as to form the hinge portion  111  (see  FIG. 2 ) of the passenger air-bag door. The convex portion  41  includes corrugations which are arranged in a width direction. 
     The first resin supply portion  50  communicates with the first supply line  51  connected to the first cavity  11   a  of the upper recess  11 . The second resin supply portion  60  communicates with the second supply line  61  and the third supply line  62 , which are connected to the second cavity  11   b  and the lower recess  21 , respectively. For exemplary purposes, the first resin supply portion  50  is intended to supply PPF resin, and the second resin supply portion  60  is intended to supply TPO resin. 
     Referring to the drawings, in particular, to  FIGS. 5 to 9 , a process of manufacturing the crash pad using the apparatus is now described. 
     While the upper core  30  and the lower core  40  are disposed at respective advanced positions thus defining a main resin layer-molding space  12   a  (see  FIG. 5 ), supply of PPF resin from the first resin supply portion  50  through the first supply line  51  results in the main resin layer  110  (see  FIG. 6 ). At this point, the convex portion  41  of the lower core  40  forms the hinge portion  111  on the lower surface of the main resin layer  110 , and the wedge  23  of the lower mold part  20  forms the tear line  112  on the lower surface of the main resin layer  110 . During the formation of the main resin layer  110 , the dam  31  of the upper core  30  protrudes into the main resin layer-molding space  12   a . Due to the presence of the dam  31 , the slit  113  is formed in the upper surface of the main resin layer  110 , in particular, in the area between the door region  100   a  and the crash pad region  100   b.    
     Prior to solidification of the PPF resin supplied into the main resin layer-molding space  12   a , the upper and lower cores  30 ,  40  are retracted to additionally define an upper resin layer-molding space  12   b  and a lower resin layer-molding space  22  (see  FIG. 7 ), and the upper resin layer-molding space  12   b  and the lower resin layer-molding space  22  are simultaneously supplied with TPO resin from the second resin supply portion  60  through the second and third supply lines  61 ,  62  (see  FIG. 8 ), resulting in the creation of the upper resin layer  120  and the lower resin layer  130 . In various embodiments, although the simultaneous supply of the same kind of resin can contribute to improvement in efficiency of the process of manufacturing the crash pad, it is also to be understood that supplying different kinds of resins through the second and third supply lines  61 ,  62  falls within the scope of the present invention. 
     During the formation of the upper and lower resin layers  120 ,  130 , the upper core  30  is positioned such that the dam  31  is partially disposed in the slit  113  of the main resin layer  110 . As shown in  FIG. 9 , when TPO resin is injected into the upper resin layer-molding space  12   b  while the slit  113  is blocked by the dam  31 , the propagation of the TPO resin to the first cavity  11   a , i.e., to the crash pad region is avoided. Even if there is partial leak of the TPO resin, the leaking resin is held only in the slit  113 , and cannot infiltrate into a clearance between the upper mold part  10  and the main resin layer  110 . In various embodiments, the slit  113  has a width of about 1-2 mm, and preferably a width of about 1-1.5 mm. At this point, the TPO resin caught in the slit  113  is invisible from the outside. Consequently, the resulting product exhibits a neat appearance on the boundary between the door region  100   a  and the crash pad region  100   b.    
     As described above, according to the present invention, a main resin layer of a crash pad is provided at upper and lower surfaces with resin layers which are more flexible than the main resin layer, and a hinge portion is provided with corrugations. Consequently, even if the hinge portion is abruptly folded by the expansionary force of a passenger air-bag, it is possible to prevent breaking the hinge portion and separation of an air-bag door at the time of deployment of the air-bag. 
     For convenience in explanation and accurate definition in the appended claims, the terms “up” or “upper”, “down”, and “lower” are used to describe features of the exemplary embodiments with reference to the positions of such features as displayed in the figures. 
     The foregoing descriptions of specific exemplary embodiments of the present invention have been presented for purposes of illustration and description. They are not intended to be exhaustive or to limit the invention to the precise forms disclosed, and obviously many modifications and variations are possible in light of the above teachings. The exemplary embodiments were chosen and described in order to explain certain principles of the invention and their practical application, to thereby enable others skilled in the art to make and utilize various exemplary embodiments of the present invention, as well as various alternatives and modifications thereof It is intended that the scope of the invention be defined by the Claims appended hereto and their equivalents.