Abstract:
A panel that realizes satisfactory strength, weight reduction and acoustic performance. Panel ( 17,18 ) has cavity ( 22 ) defined by inside thin sheet ( 23 ) fixed to the inside surface of outside thin sheet ( 21 ), and the cavity ( 22 ) is filled with foam ( 24 ). Preferably, the foam ( 24 ) consists of a rubber acoustic material of high expansion. For the inside thin sheet ( 23 ), not only circumferential edge portion ( 26 ) and circumferential side portion ( 25 ) for defining the cavity ( 22 ) but also recessed portion ( 27 ) for increasing the panel strength is draw formed on the side of outside thin sheet ( 21 ). The bottom surfaces of the circumferential edge portion ( 26 ) and recessed portion ( 27 ) of the inside thin sheet ( 23 ) are bonded to the outside thin sheet ( 21 ) by a thermosetting adhesive.

Description:
[0001]    This is a U.S. national phase application under 35 U.S.C. §371 of International Patent Application No. PCT/JP2007/062742 filed Jun. 26, 2007, and claims the benefit of Japanese Application No. 2007-005524, filed Jan. 15, 2007. The International Application has not been published at the time of this filing. The contents of these applications are incorporated herein in their entirety. 
     
    
     TECHNICAL FIELD 
       [0002]    The present invention relates to a panel provided with a foam material and a method for manufacturing the same. 
       BACKGROUND ART 
       [0003]    There has been a cover body structure obtained by welding an inner reinforcing plate having a concave part to an outer panel of construction machinery (for example, see Japanese Patent Application Laid-Open No. 09-228412 (“JP &#39;412”) (e.g., page 3, FIG. 7)). 
         [0004]    There has been an engine cover having a sound insulating material or a sound absorbing material as a lining member attached to the inner side of a cover body in construction machinery (for example, see Japanese patent Publication No. 3457804 (“JP &#39;804”) (e.g., page 2, FIG. 1)). 
         [0005]    In JP &#39;412, the cover body structure becomes heavy in order to obtain sufficient strength using the inner reinforcing plate, and welding traces tend to appear on the outside. Also, neither sound insulating performance nor sound absorbing performance is sufficient. 
         [0006]    In JP &#39;804, the lining member such as the sound absorbing material is visible from the outside when opening the engine cover, creating an unattractive appearance and insufficient strength. 
         [0007]    The present invention has been made in consideration of the above-mentioned problems, and it is an object of the present invention to provide a panel capable of obtaining sufficient strength, weight reduction and sound absorbing performance, and a method for manufacturing the panel. 
       SUMMARY OF THE INVENTION 
       [0008]    The invention provides a panel including: 
         [0009]    an outer thin plate; 
         [0010]    an inner thin plate fixed to an inner surface of the outer thin plate and forming a space; and 
         [0011]    a foam material filled in the space. 
         [0012]    The invention according to the below description provides the panel according to the above description, wherein the inner thin plate is bonded to the outer thin plate. 
         [0013]    The invention provides the panel according to the above, wherein the outer thin plate has a turned-up edge part which is a turned-up perimetrical edge part crimped to and bonded to the inner thin plate. 
         [0014]    The invention provides the panel according to any of the above, wherein a plurality of foam materials are arranged in one space. The invention provides the panel, further including: 
         [0015]    a fitting base member fixed to an inner surface of an end edge part of the outer thin plate; and 
         [0016]    a hinge welded to the fitting base member. 
         [0017]    A method for manufacturing a panel including the steps of: 
         [0018]    providing a non-foam material of a foamable filler on an outer thin plate; 
         [0019]    fixing an inner thin plate forming a space corresponding to the non-foam material to the outer thin plate; 
         [0020]    foaming the non-foam material by a baking coating heating device to fill the foam material in the space; and 
         [0021]    finishing at least the baking coating of the outer thin plate by the baking coating heating device. 
         [0022]    The method for manufacturing the panel further includes the steps of: 
         [0023]    supplying a thermosetting adhesive between the outer thin plate and the inner thin plate; and 
         [0024]    curing the adhesive by the baking coating heating device. 
         [0025]    The method for manufacturing the panel further includes the steps of: 
         [0026]    partially omitting the application of an adhesive when applying the adhesive onto a perimetrical edge part of the outer thin plate; and 
         [0027]    turning up the entire perimetrical edge part of the outer thin plate and fixing the perimetrical edge part to the perimetrical edge part of the inner thin plate.
   The method for manufacturing the panel, further includes the steps of:   
 
         [0029]    drilling an inner hole in the inner thin plate; and 
         [0030]    laser processing an outer hole to the outer thin plate in the inner hole. 
         [0031]    According to the invention, a three-layer structure having the outer thin plate, the inner thin plate and the foam material filled in the space of the inner thin plate can provide sufficient strength and weight reduction and can provide sound absorbing performance by the foam material. 
         [0032]    According to the invention, since the inner thin plate is bonded to the outer thin plate, the inner thin plate can be fixed more easily than welding, and the exposure of welding traces having a poor appearance on the outside can be prevented or reduced. 
         [0033]    According to the invention, since the turned-up edge part formed by turning up the perimetrical edge part of the outer thin plate is crimped to and bonded to the inner thin plate, sufficient bonding strength between the outer thin plate and the inner thin plate can be secured by crimping strength and adhesive strength, and the sealing performance of a bonded part can be secured. 
         [0034]    According to the invention, the economical foaming shape corresponding to the shape of the space can be obtained by the plurality of foam materials. 
         [0035]    According to the invention, the fitting strength required for the hinge can be secured by welding the hinge to the end edge part of the outer thin plate via the fitting base member. 
         [0036]    According to the invention, since the non-foam material of the foamable filler provided on the outer thin plate is foamed by the baking coating heating device to fill the foam material in the space of the inner thin plate, the non-foam material can be efficiently foamed in the baking coating. Thereby, the manufacturing efficiency can be enhanced and the baking coating heating device can be efficiently operated. 
         [0037]    According to the invention the thermosetting adhesive can be efficiently cured upon baking coating by the baking coating heating device, and the non-foam material can be efficiently foamed. Thereby, the manufacturing efficiency can be enhanced, and the baking coating heating device can be efficiently operated. 
         [0038]    According to the invention, air can be removed when the non-foam material of the foamable filler is foamed from the non-applied part of the adhesive by partially omitting the application of the adhesive when the adhesive is applied onto the perimetrical edge part of the outer thin plate, and a smooth foaming operation can be secured. 
         [0039]    According to the invention, the outer hole having any shape can be easily opened in the outer thin plate in the inner hole by laser processing by drilling the inner hole in the inner thin plate. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0040]      FIG. 1  is a sectional view showing an embodiment of a panel according to the present invention; 
           [0041]      FIG. 2  is a sectional view of a hinge fitting part of the panel; 
           [0042]      FIG. 3  is a sectional view showing an example of a method for manufacturing the panel; FIG. (a) shows a state where a non-foam material is provided on an outer thin plate; FIG. (b) shows a state where a non-foam material is foaming; FIG. (c) shows a state where the foam formation of a foam material is completed; 
           [0043]      FIG. 4  is a perspective view of a hydraulic backhoe using the panel; 
           [0044]      FIG. 5  is a perspective view showing an assembly example of an outer thin plate and inner thin plate which constitute the panel; FIG. (a) shows a disassembly state thereof; FIG. (b) shows an assembly completion state thereof; 
           [0045]      FIG. 6  is a perspective view showing a hole processing example of the panel; and 
           [0046]      FIG. 7  is a cross section along the line VII-VII of  FIG. 6 . 
       
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
       [0047]    Hereinafter, the present invention will be described in detail with reference to an embodiment shown in  FIGS. 1 to 7 . 
         [0048]    As shown in  FIG. 4 , a hydraulic backhoe  10 , which is an operating machine, includes a lower travelling body  11  and an upper turning body  12  turnably provided on the lower travelling body  11 . On the upper turning body  12 , there is mounted a cab  13 , a working device  14 , an engine  15 , and an air filter and a radiator which are related to the engine  15 , or the like. The engine  15  is covered with an engine hood  16 , and the air filter and the radiator are covered with double swinging side door panels (hereinafter, simply referred to as panel)  17  and  18 .  FIG. 5  shows the air filter side panel  17 .  FIG. 6  shows the radiator side panel  18 . 
         [0049]      FIG. 1  shows a partially expanded view of the panels  17  and  18 . Each of the panels  17  and  18  is provided with an outer thin plate  21 , an inner thin plate  23  fixed to the inner surface of the outer thin plate  21  and forming a space  22 , and a foam material  24  filled in the space  22 . The foam material  24  is preferably a highly foamable rubber sound absorbing material having a volume expansion coefficient of about 20 times. 
         [0050]    In the inner thin plate  23 , a perimetrical side part  25  and a perimetrical edge part  26  for forming the space  22 , and a concave part  27  for enhancing the strength of a panel are drawn to the side of the outer thin plate  21 . The bottom faces of the perimetrical edge part  26  and concave part  27  of the inner thin plate  23  are bonded to the outer thin plate  21  using a thermosetting adhesive. 
         [0051]    That is, the perimetrical side part  25 , perimetrical edge part  26  and concave part  27  projected to the side of the outer thin plate  21  are formed in the inner thin plate  23  by a drawing process. Thereby, the space  22  is formed between the perimetrical side part  25  and the concave part  27  by bonding the bottom faces of the perimetrical edge part  26  and concave part  27  to the outer thin plate  21 . 
         [0052]    The concave part  27  bonded to the outer thin plate  21  can enhance the strength of the panel and reduce the volume of the space  22  between the outer thin plate  21  and the inner thin plate  23  to reduce the amount of the required foam material  24 . 
         [0053]    There is provided a turned-up edge part  28  formed by turning up the perimetrical edge part in the outer thin plate  21 . The turned-up edge part  28  is crimped to the perimetrical edge part  26  of the inner thin plate  23 , and is bonded by a thermosetting adhesive. 
         [0054]    As shown in  FIG. 2 , referring to the panels  17  and  18 , a thick plate-like fitting base member  31  is fixed to the inner surface of the end edge part of the outer thin plate  21  by a thermosetting adhesive. A fitting plate  33  of one side of a hinge  32  is welded to the fitting base member  31 . That is, the strength of the circumference of the hinge  32  is mostly required, and must be reinforced, so that one leg part  34  and the other leg part  35  of the fitting base member  31  are bonded along the hinge fitting edge part of the outer thin plate  21 , and the fitting plate  33  of the hinge  32  is welded to a plane-like fitting face part  36 . The turned-up edge part  28  formed by turning up a side end edge part of the outer thin plate  21  is crimped to one leg part  34  of the fitting base member  31 , and bonded by a thermosetting adhesive. The perimetrical edge part  26  of the inner thin plate  23  is stacked on the other leg part  35  of the fitting base member  31 , and is bonded by a thermosetting adhesive. 
         [0055]    Next, as shown in  FIG. 3(   a ), referring to a method for manufacturing the panels  17  and  18 , non-foam materials  24   a  of the foamable filler are provided on the outer thin plate  21 . The inner thin plate  23  forming the space  22  corresponding to the non-foam materials  24   a  is fixed to the outer thin plate  21 . At this time, a thermosetting adhesive is supplied between contact surfaces of the outer thin plate  21  and inner thin plate  23 . The non-foam materials  24   a  are stuck on the outer thin plate  21  so that a plurality of rubber sound absorbing materials are arranged at a proper interval in one space  22 . 
         [0056]    The adhesive is cured by a baking coating heating device. Furthermore, as shown in  FIGS. 3(   b ) and  3 ( c ), the non-foam materials  24   a  are foamed by the baking coating heating device to fill the foam materials  24  in the space  22 . Coating materials previously sprayed on the outer thin plate  21  and the inner thin plate  23  are baked by the baking coating heating device. 
         [0057]    For example, it is necessary to heat the adhesive at 150° C. for 5 minutes in order to cure the adhesive; it is necessary to heat the foam material  24  at 180° C. for 20 minutes in order to complete the foam formation of the foam material  24 ; and baking heating at 200° C. for 20 minutes is required in order to complete the baking coating. Thereby, all the heatings can be performed by using the existing baking coating heating device. 
         [0058]    In the manufacture of the panel  17  shown in  FIG. 5(   a ), a thermosetting adhesive  38  is applied onto three perimetrical edge parts  28   b,    28   c,    28   d,    28   e  and  28   f  of a right and left side edges and lower side edge among perimetrical edge parts  28   a ,  28   b,    28   c,    28   d,    28   e  and  28   f  of the outer thin plate  21 . As shown in  FIG. 5(   b ), the entire perimetrical edge parts  28   a  to  28   f  of the outer thin plate  21  are turned-up without applying the thermosetting adhesive  38  onto the perimetrical edge part  28   a  of the upper side edge, and the perimetrical edge parts  28   a  to  28   f  are fixed to the perimetrical edge part of the inner thin plate  23 . 
         [0059]    That is, three side edges of the right and left side edges and lower side edge of the outer thin plate  21  are bent and bonded. However, only the upper side edge is bent, and is not bonded. Alternatively, the adhesive  38  may be intermittently applied in the form of perforations over the entire perimetrical edge part of the outer thin plate  21 , or the adhesive  38  may be partially and intentionally removed. In short, when the adhesive  38  is applied onto the perimetrical edge part of the outer thin plate  21 , the application of the adhesive  38  is partially omitted. On the other hand, the entire perimetrical edge part of the outer thin plate  21  is turned-up. 
         [0060]    The panel  18  shown in  FIGS. 6 and 7  is also similarly bent and bonded. However, two metal plates cannot be simultaneously laser-processed when forming a hole in the panel  18  prepared by stacking two metal plates. Thereby, an inner hole  41  is drilled in the inner thin plate  23 , and, a plurality of outer holes  42  are laser-processed and drilled in the outer thin plate  21  in the inner hole  41 . 
         [0061]    That is, it is technically difficult to form a hole in two layers of the outer thin plate  21  and inner thin plate  23  simultaneously by laser processing. Thereby, when the hole is formed in such a two-layer panel, the inner hole  41  is previously formed in a concave part  43  of the inner thin plate  23 . The perimetrical edge part of the inner hole  41  is bonded to the outer thin plate  21 , and the outer hole  42  having any shape is then opened in the outer thin plate  21  corresponding to an inner hollow part of the inner hole  41  by laser processing. 
         [0062]    Next, the effects of the illustrated embodiment will be described. 
         [0063]    As shown in  FIG. 1 , sufficient strength and weight reduction can be obtained by a three-layer structure of the outer thin plate  21 , inner thin plate  23  and foam material  24  filled in the space  22  of the inner thin plate  23 . That is, the foam material  24  is filled in the space  22  between the outer thin plate  21  and the inner thin plate  23 , and they are wholly integrated. Thereby, the strength shortage of each of the outer thin plate  21  and inner thin plate  23  is compensated, and the strength can be enhanced as a whole. 
         [0064]    The sound absorbing performance can be obtained by the foam material  24 , and the sound absorbing material bonded to the inner surface of the side door panel of the conventional engine cover can be removed. 
         [0065]    Since the inner thin plate  23  is bonded to the outer thin plate  21 , the inner thin plate  23  is fixed more easily than welding, and the exposure of welding traces having a poor appearance on the outside can be prevented or reduced. 
         [0066]    Since the turned-up edge part  28  formed by turning up the perimetrical edge part of the outer thin plate  21  is crimped to and bonded to the perimetrical edge part  26  of the inner thin plate  23 , sufficient bond strength between the outer thin plate  21  and the inner thin plate  23  can be secured by crimping strength and adhesive strength, and the sealing performance of a bonded part can be secured. 
         [0067]    The economical foaming shape corresponding to the shape of the space  22  can be obtained by the plurality of foam materials  24 . 
         [0068]    As shown in  FIG. 2 , the fitting strength required for the hinge  32  can be secured by welding the hinge  32  to the end edge part of the outer thin plate  21  via the fitting base member  31 . 
         [0069]    As shown in  FIG. 3 , since the non-foam material  24   a  of the foamable filler set on the outer thin plate  21  is foamed by the baking coating heating device to fill the foam material  24  in the space  22  of the inner thin plate  23 , the non-foam material  24   a  can be efficiently foamed in the baking coating. Thereby, the manufacturing efficiency can be enhanced, and the baking coating heating device can be efficiently operated. 
         [0070]    Furthermore, the thermosetting adhesive can be efficiently cured upon baking coating by the baking coating heating device, and the non-foam material  24   a  can be efficiently foamed. Thereby, the manufacturing efficiency can be enhanced, and the baking coating heating device can be efficiently operated. 
         [0071]    As shown in  FIG. 5 , air can be removed when the non-foam material  24   a  of the foamable filler is foamed from the non-applied part of the adhesive  38  by intermittently applying the adhesive  38 , and partially and intentionally removing the adhesive  38  to partially omit the application of the adhesive  38  when the adhesive  38  is applied onto the perimetrical edge part of the outer thin plate  21 . Therefore, a smooth foaming operation can be secured, and the generation of problems of thin plate burst or the like in complete sealing can be prevented. 
         [0072]    As shown in  FIGS. 6 and 7 , the outer hole  42  having any shape can be easily opened in the outer thin plate  21  in the inner hole  41  by laser processing by drilling the inner hole  41  in the inner thin plate  23 . 
         [0073]    In one example shown, referring to the side door panel used for a conventional hydraulic backhoe, a thick sheet metal having a thickness of 1.6 mm is further reinforced. On the other hand, as the outer thin plate  21 , a thin sheet metal having a thickness of 0.8 to 1.2 mm is used, and as the inner thin plate  23 , a thin sheet metal having a thickness of about 0.35 to 0.6 mm is used. The thin plates  21  and  23  are laminated using an adhesive. The thin plates  21  and  23  are sealed by the perimetrical edge part  28  formed by turning up the perimetrical edge part of the outer thin plate  21 . The non-foam material  24   a  of a foamable rubber sound absorbing material is laminated on the inner surface of the outer thin plate  21  facing the space  22  between the thin plates  21  and  23  before laminating them. This non-foam material  24   a  is foamed in a heat process in baking the coating so that the material is filled in a part or all of the space  22 . Since the foam material  24  has reinforcing effect and sound absorbing performance, even a large-sized panel can suppress the weight to attain weight reduction and can enhance sound insulating performance and strength. The panel can strengthen the rigidity of a door, can substantially realize a reduction in noise of a standard door, and has excellent appearance. 
         [0074]    The present invention can be used for an opening/closing door panel, a non-opening/closing fixed panel, and a method for manufacturing the panels.