Abstract:
A package structure of an inverter apparatus includes at least four metal column supports arranged vertically to be spaced apart from each other, and sheet-metal bent beams connecting the column supports in transverse direction and longitudinal direction to form rectangular package structure. The metal column support is an aluminum die-cast support, and the sheet-metal bent beam has a U-shape with sharp edges in cross section.

Description:
BACKGROUND OF THE INVENTION AND RELATED ART STATEMENT  
       [0001]     The present invention relates to a package structure of an inverter apparatus and a method of manufacturing the same, and more particularly to a package structure of an inverter apparatus and a method of manufacturing the same that can be suitably applied to increase the strength of the package structure.  
         [0002]     Conventionally, metallic packages formed by combinations of aluminum die-cast members and metal sheets so as to support heavy components such as an electrolytic capacitor and a cooling fin have been used for inverter apparatuses.  
         [0003]      FIG. 6  is an exploded perspective view showing a package structure of a conventional inverter apparatus, and  FIG. 7  is an exploded perspective view showing the interior of the package structure of the conventional inverter apparatus.  
         [0004]     As shown in  FIG. 6 , in the package structure of the inverter apparatus, aluminum die-cast members  101   a  and  101   b  having substantially the same length as the width of the inverter apparatus are provided in an upper part and a lower part, respectively. The upper and lower aluminum die-cast members  101   a  and  101   b  are connected to each other by side metal sheets  103   a  and  103   b  which constitute casings of both sides of the inverter apparatus, a frame metal sheet  106 , and a rear plate  112 .  
         [0005]     A cooling fin  113  and an electrolytic capacitor  115  are mounted on the frame metal sheet  106 , and a ceiling cover  102  is mounted on a ceiling surface of the inverter apparatus. It should be noted that the side metal sheets  103   a  and  103   b , frame metal sheet  106 , and rear plate  112  can be connected to the aluminum die-cast members  101   a  and  101   b  by screws.  
         [0006]     As shown in  FIG. 7 , metal sheets on which built-in components such as a main circuit terminal block  110  and a printed-circuit board  111  are mounted on the side sheet-metals  103   a  and  103   b  and supporting sheet-metals mounted thereon.  
         [0007]     For example, a method in which a front cover is placed on four supports with high strength for ventilating covers mounted on a ceiling surface and a bottom surface and is then secured to the supports by screws so as to reduce man-hours has been disclosed in Japanese Laid-Open Patent Publication (Kokai) No. 2005-243741.  
         [0008]     In the package structure of the conventional inverter apparatus, however, the package strength of the inverter apparatus is secured by the upper and lower aluminum die-cast members  101   a  and  101   b , side metal sheets  103   a  and  103   b , and frame metal sheet  106 . Thus, to install heavy components such as a cooling fin  113  and an electrolytic capacitor  115  in the early stage of assembly, the side metal sheets  103   a  and  103   b  are mounted on the aluminum die-cast members  101   a  and  101   b  in the early stage of assembly so as to secure s strength of the package, and therefore, there are some limitations as to tools for assembly.  
         [0009]     Also, in the package structure of the conventional inverter apparatus, the aluminum die-cast members  101   a  and  101   b  having substantially the same length as the width of the inverter apparatus are used. Therefore, the shapes of the aluminum die-cast members  101   a  and  101   b  are limited by the width of the inverter apparatus. Thus, it is necessary to fabricate aluminum die-cast members  101   a  and  101   b  for each width of inverter apparatus, which significantly increases costs for manufacturing the aluminum die-cast members.  
         [0010]     Further, since built-in components such as a main circuit terminal block  110  and a printed-circuit board  111  are mounted on the side metal sheets  103   a  and  103   b  which are substantially flat-shaped, there may be cases where built-in components, which are sometimes very fragile, are broken by resonance of the side metal sheets  103   a  and  103   b . Accordingly, the package structure of the conventional inverter apparatus has to be reinforced by installing beams in transverse direction or the like.  
         [0011]     An objective of the present invention is to provide a package structure of an inverter apparatus that can support heavy components without using side metal sheets, so that there is no limitation on the width of the inverter apparatus by the size of aluminum die-cast members.  
         [0012]     Further objectives and advantages of the invention will be apparent from the following description of the invention.  
       SUMMARY OF THE INVENTION  
       [0013]     To achieve the objective, a package structure of an inverter apparatus includes aluminum die-cast supports disposed at at least four corners of the inverter apparatus, and sheet-metal beams bent like a letter U with sharp bent edges, connecting the aluminum die-cast supports in the transverse direction and the longitudinal direction of the inverter apparatus.  
         [0014]     With this arrangement, since the inverter apparatus can be supported by the aluminum die-cast supports and the sheet-metal beams, adequate package strength can be secured without using flat-shaped side metal sheets. Also, since the aluminum die-cast supports are connected in transverse direction by the sheet-metal beams, the width of the inverter apparatus can be defined by distances between the aluminum die-cast members, and therefore the width of the inverter apparatus can be adjusted without changing the size of the aluminum die-cast supports.  
         [0015]     For this reason, the side metal sheets can be installed after the installation of heavy components such as a cooling fin and an electrolytic capacitor, and therefore, there is no limitation as to tools for assembly and assembling efficiency can be enhanced. Also, it is unnecessary to fabricate the aluminum die-cast supports for each of inverter widths, and therefore, it allows to avoid additional costs for manufacturing the inverter apparatus.  
         [0016]     Preferably, the aluminum die-cast supports comprise metal sheet mounting taps for fixing metal sheets, sheet-metal beam mounting notches for mounting sheet-metal beams, and unit hanging holes for hanging the inverter apparatus.  
         [0017]     With this arrangement, the metal sheets can be mounted on the aluminum die-cast supports while securing the mounting locations precisely, and also adequate package strength can be secured while enhancing assembling efficiency.  
         [0018]     Preferably, a main circuit terminal block and a printed-circuit board incorporated in the inverter apparatus are mounted on the sheet-metal beams connecting the aluminum die-cast supports in the longitudinal direction of the inverter apparatus.  
         [0019]     With this arrangement, it is unnecessary to mount the main circuit terminal block and the printed-circuit board on the flat-shaped side metal sheets, and therefore, it is possible to prevent such built-in components, which are sometimes very fragile, from being broken by resonance of the side metal sheets.  
         [0020]     To achieve the above objective, a method of fabricating a package structure of an inverter apparatus includes a step of connecting U-shaped sheet-metal beams with sharp bent edges to bases of aluminum die-cast supports, disposed at at least four corners of the inverter apparatus, in transverse direction of the inverter apparatus, a step of mounting ceiling covers and a bottom cover on the aluminum die-cast supports connected in transverse direction of the inverter apparatus, a step of connecting U-shaped sheet-metal beams to the aluminum die-cast supports in a longitudinal direction of the inverter apparatus, a step of mounting frame sheet-metals, on which an electrolytic capacitor and a cooling fin are to be mounted, to the aluminum die-cast supports to which the U-shaped sheet-metal beams are connected in the longitudinal direction of the inverter apparatus, a step of mounting a main circuit terminal block and a printed-circuit board on the U-shaped sheet-metal beams connected to the aluminum die-cast supports in the longitudinal direction of the inverter apparatus, and a step of mounting side metal sheets on the inverter apparatus after mounting the main circuit terminal block and the printed-circuit board on the U-shaped sheet-metal beams.  
         [0021]     With this arrangement, since the side metal sheets can be mounted on the inverter apparatus after the installation of heavy components such as a cooling fin and an electrolytic capacitor, it makes it easier to access to the interior of the package and assemble the inverter apparatus. Also, the side metal sheets can be mounted on the inverter apparatus in the final step of assembly, so that damages to coating surfaces of the side metal sheets can be prevented.  
         [0022]     The above and other objects, features, and advantages of the invention will become more apparent from the following detailed description taken in conjunction with the accompanying drawings. 
     
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0023]      FIG. 1  is a perspective view showing a package structure of an inverter apparatus with a front cover removed according to an embodiment of the present invention;  
         [0024]     FIGS.  2 ( a ) and  2 ( b ) are exploded perspective views showing how to assemble aluminum die-cast supports according to an embodiment of the present invention, wherein  FIG. 2 ( a ) shows how to assemble aluminum die-cast supports on the ceiling cover side and sheet-metal beams in transverse direction, and  FIG. 2 ( b ) shows how to assemble the aluminum die-cast supports on the bottom cover side and sheet-metal beams in transverse direction;  
         [0025]     FIGS.  3 ( a ) and  3 ( b ) are exploded perspective views showing how to assemble aluminum die-cast supports and sheet-metal beams in longitudinal direction according to the embodiment;  
         [0026]      FIG. 4  is an exploded perspective view showing how to assemble side metal sheets in the inverter package structure according to the embodiment;  
         [0027]     FIGS.  5 ( a ) to  5 ( h ) are views showing the construction of an aluminum die-cast support according to the embodiment;  
         [0028]      FIG. 6  is an exploded perspective view showing a package structure of a conventional inverter apparatus; and  
         [0029]      FIG. 7  is an exploded perspective view showing the interior of the package structure of the conventional inverter apparatus. 
     
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS  
       [0030]     A package structure of an inverter apparatus and a method of manufacturing the same according to an embodiment of the present invention will now be described with references to the drawings.  
         [0031]      FIG. 1  is a perspective view showing a package structure of an inverter apparatus with a front cover removed according to an embodiment of the present invention.  FIG. 2 ( a ) is an exploded perspective view useful showing how to assemble aluminum die-cast supports on the ceiling cover side and sheet-metal beams in the transverse direction according to the embodiment.  FIG. 2 ( b ) is an exploded perspective view useful for showing how to assemble aluminum die-cast supports on the bottom cover side and sheet-metal beams in transverse direction according to the embodiment.  FIG. 3 ( a ) is an exploded perspective view useful for showing how to assemble aluminum die-cast supports and sheet-metal beams in longitudinal direction according to the embodiment.  FIG. 3 ( b ) is an exploded perspective view showing how to assemble aluminum die-cast supports and sheet-metal beams in longitudinal direction according to the embodiment.  FIG. 4  is an exploded perspective view showing how to assemble side metal sheets in the inverter package structure according to the embodiment.  
         [0032]     As shown in FIGS.  1  to  4 , in the package structure of the inverter apparatus, aluminum die-cast supports  1   a  to  1   d  are disposed at four corners of the inverter apparatus. The aluminum die-cast supports  1   a  and  1   b  are connected to each other in transverse direction by a sheet-metal beam  6   a  bent like a letter U with sharp bent edges, and the aluminum die-cast supports  1   c  and  1   d  are connected to each other in transverse direction by a sheet-metal beam  6   b  bent like a letter U with sharp bent edges.  
         [0033]     The aluminum die-cast supports  1   b  and  1   d  are connected to each other in the longitudinal direction by a sheet-metal beam  14   a  bent like a letter U with sharp bent edges, and the aluminum die-cast supports  1   a  and  1   c  are connected to each other in the longitudinal direction by a sheet-metal beam  14   b  bent like a letter U with sharp bent edges. Ceiling covers  2  and  3   b  are mounted on the aluminum die-cast supports  1   a  and  1   b , and a bottom cover  3   a  is mounted on the aluminum die-cast supports  1   c  and  1   d . A mounting foot  4   a  is mounted on the bottom cover  3   a , and a mounting foot  4   b  is mounted on the ceiling cover  3   b.    
         [0034]     Frame metal sheets  9   a  and  9   b  on which an electrolytic capacitor and a cooling fin  13  are mounted are mounted on the aluminum die-cast supports  1   a  to  1   d , and a main circuit terminal block  10  and a printed-circuit board  11  are mounted on the sheet-metal beams  14   a  and  14   b . Further, side metal sheets  5   a  and  5   b  are mounted on respective sides of the inverter apparatus.  
         [0035]     In constructing the package structure in  FIG. 1 , the aluminum die-cast supports  1   a  to  1   d  are disposed at respective four corners of the inverter apparatus as shown in  FIG. 2 . The sheet-metal beams  6   a  and  6   b  are mounted on the bases of the aluminum die-cast supports  1   a  to  1   d  by screws, and the aluminum die-cast supports  1   a  to  1   d  are connected to each other in the transverse direction of the inverter apparatus. By changing the length of the sheet-metal beams  6   a  and  6   b , the width of the inverter apparatus can be arbitrarily changed.  
         [0036]     The ceiling covers  2  and  3   b  and the bottom cover  3   a  are secured to the aluminum die-cast supports  1   a  to  1   d , which are connected in the transverse direction, by screws. Also, a frame metal sheet  7  is secured to the ceiling cover  3   b  by screws. Further, the mounting foot  4   a  is secured to the bottom cover  3   a  by screws, and the mounting foot  4   b  is secured to the ceiling over  3   b  by screws.  
         [0037]     Next, as shown in  FIG. 3 , the ceiling covers  2  and  3   b  and the bottom cover  3   a  are disposed in opposed relation in such a manner that the mounting foots  4   a  and  4   b  face outward. The sheet-metal beams  14   a  and  14   b  are then secured to the aluminum die-cast supports  1   a  to  1   d  by screws, so that the aluminum die-cast supports  1   a  to  1   d  are connected in the longitudinal direction of the inverter apparatus. By changing the lengths of the sheet-metal beams  14   a  and  14   b , the longitudinal length of the inverter apparatus can be arbitrarily changed.  
         [0038]     The frame metal sheets  9   a  and  9   b  are then secured to the aluminum die-cast supports  1   a  to  1   d , which are connected in the longitudinal direction of the inverter apparatus by screws, and the electrolytic capacitor and the cooling fin  13  are mounted on the frame metal sheets  9   a  and  9   b . A metal sheet  8  and a rear plate  12  are then secured to the aluminum die-cast supports  1   a  to  1   d  by screws.  
         [0039]     Next, as shown in  FIG. 4 , the main circuit terminal block  10  and the printed-circuit board  11  are mounted on the sheet-metal beams  14   a  and  14   b  connected to the aluminum die-cast supports  1   a  to  1   d , and thereafter, the side metal sheets  5   a  and  5   a  are secured to the aluminum die-cast supports  1   a  to  1   d  and the sheet-metal beams  14   a  and  14   b  by screws.  
         [0040]     As a consequence, the aluminum die-cast supports  1   a  to  1   d  and the sheet-metal beams  6   a ,  6   b ,  14   a , and  14   b  can support the inverter apparatus, and adequate package strength can be secured without using the flat-shaped side metal sheets  5   a  and  5   b . Also, since the aluminum die-cast supports  1   a  to  1   d  are connected in transverse direction by the sheet-metal beams  6   a  and  6   b , the width of the inverter apparatus can be defined by distances between the aluminum die-cast supports  1   a  to  1   d , and therefore, the width of the inverter apparatus can be adjusted without changing the size of the aluminum die-cast supports  1   a  to  1   d.    
         [0041]     For this reason, the side metal sheets  5   a  and  5   b  can be installed after the installation of heavy components such as the cooling fin  13  and the electrolytic capacitor, and therefore, there is no more limitation as to tools used for assembly, and assembling efficiency can be enhanced. Also, it is unnecessary to fabricate the aluminum die-cast supports  1   a  to  1   d  for each of inverter widths, and therefore, the cost for manufacturing the inverter apparatus can be prevented from being increased.  
         [0042]     FIGS.  5 ( a ) to  5 ( h ) are views showing the construction of each aluminum die-cast support according to the embodiment.  
         [0043]     As shown in FIGS.  5 ( a )- 5 ( h ), the aluminum die-cast supports  1   a  to  1   d  are provided with sheet metal mounting taps  21   a  to  21   k , sheet-metal beam mounting notches  22   a  and  22   b , and unit hanging holes  23   a  and  23   b . On the other hand, the sheet-metal beams  6   a ,  6   b ,  14   a , and  14   b  may be burred.  
         [0044]     Metal sheets such as the sheet-metal beams  6   a ,  6   b ,  14   a , and  14   b  and the frame metal sheets  9   a  and  9   b  are secured to the aluminum die-cast supports  1   a  to  1   d  by screws through the metal sheet mounting taps  21   a  to  21   k , and metal sheets such as sheet-metal beams  6   a  and  6   b  are fitted into the sheet-metal beam mounting notches  22   a  and  22   b.    
         [0045]     As a consequence, it is possible to mount the sheet metals on the aluminum die-cast supports  1   a  to  1   d  while securing the mounted locations adequately, and therefore, it is possible to obtain adequate package strength while enhancing assemble efficiency.  
         [0046]     Although in the present embodiment, the aluminum die-cast supports  1   a  to  1   d  are disposed at four corners of the inverter apparatus, the present invention is not limited to this, but package strength can be further increased by increasing the number of supports, for example, additional aluminum die-cast supports may be provided in longitudinal direction of the inverter apparatus. That is, the number of aluminum die-cast supports can be determined depending on required package strength.  
         [0047]     The disclosure of Japanese Patent Application No. 2006-140590 filed on May 19, 2006 is incorporated as a reference.  
         [0048]     While the invention has been explained with reference to the specific embodiments of the invention, the explanation is illustrative and the invention is limited only by the appended claims.