Abstract:
The present invention provides an air cooling means forcibly cools inside of an operation box of controlling an engine generator by using engine cooling air. An engine generator has a generator driven by an engine and an operation box housing a controller for the generator. The engine is cooled by a fan. The operation box has an upper opening for taking outside air and a lower opening for exhausting air to the outside from the operation box. The lower opening is disposed so as to be oriented to the cooling air flow generated by the fan. A bottom plate of the operation box is disposed obliquely to an air intake port for taking air to the engine by the cooling fan for the engine, and the lower opening is opened in the bottom plate.

Description:
[0001]    The present invention relates to an engine operating machine and, more particularly, relates to an engine operating machine having a configuration of increasing an effect of cooling an operation box. 
       BACKGROUND ART 
       [0002]    An engine generator as an operating machine driven by an engine is provided with an operation board or an operation box. The operation box has therein a device (AVR) for automatically controlling output voltage generated by the engine generator, an electric wire, and the like, and produces heat when current flows. The heat increases temperature in the operation box and exerts an adverse influence on electronic parts. Consequently, a measure to avoid temperature rise is taken. 
         [0003]    For example, Japanese Utility Model Application Laid-Open (JP-U) No. 63-125129 discloses an engine generator having a control box disposed on the generator. A port communicated with the control box is provided in a rear-part peripheral wall of the generator, and the control box has an outside air intake port. In the engine generator, the inside of the control box is cooled by making outside air taken from the outside air intake port, pass through the communication port, and circulated in the casing of the generator by suction force generated by a ventilation fan. 
         [0004]    Japanese Utility Model Application Laid-Open (JP-U) No. 05-58826 discloses a structure, in a soundproof case in which cooling air from a cooling fan is sucked in a fan case of an engine, circulated around the engine, and discharged and, an operation board is positioned on the front side of an upper half of the fan case. 
       CITATION LIST 
     Patent Literature 
       [0000]    
       
         Patent Literature 1; Japanese Utility Model Application Laid-open (JP-U) No. 63-125129 
         Patent Literature 2; Japanese Utility Model Application Laid-open (JP-U) No. 05-58826 
       
     
       SUMMARY OF INVENTION 
     Technical Problem 
       [0007]    In the device described in Japanese Utility Model Application Laid-Open (JP-U) No. 63-125129, the guidance port for taking air into the generator by the ventilation fan opens to the inner space covered with a rear-part case. Consequently, outside air introduced from the control box via the communication port and outside air introduced from an air supply port formed in the rear-part case are merged in the inner space and sucked to the guidance port. That is, the outside air from the air supply port is directly introduced to the guidance port and, on the other hand, the outside air from the outside air intake port in the control box passes through the communication port and is introduced to the guidance port. Since the flow path resistance in the air supply path extending from the outside air intake port in the control box via the communication port to the guidance port is higher than that in the air supply path by which outside air is introduced from the air supply port to the guidance port, the flow rate of air which flows in the guidance port via the communication port becomes lower than that of air which directly flows from the air supply port to the guidance port. There is consequently a problem such that an effect of sufficient cooling the control box is not easily obtained. 
         [0008]    Further, in the device described in Japanese Utility Model Application Laid-Open (JP-U) No. 63-125129, the outside air intake port is provided in the side wall of the control box, and the wall is adjacent to the communication port. Consequently, the outside air does not easily flow in space adjacent to a wall apart from the outside air intake port, so that the cooling effect is small in the space. 
         [0009]    The soundproof case described in Japanese Utility Model Application Laid-Open (JP-U) No. 5-58826 is constructed so that radiation heat from the engine is not easily transmitted to the operation board. The operation board is provided in an upper part of a soundproof room partitioned by a partition plate provided between the soundproof room and an air supply room, and air flow is not easily generated around the operation board. There is consequently a problem that heat tends to stay. 
         [0010]    In view of the problems, an object of the present invention is to provide an engine operating machine with an increased effect of cooling an operation box by making cooling air generated by operation of an engine effectively acted. 
       Solution to Problem 
       [0011]    A first feature of the present invention to accomplish aforementioned object is an engine operating machine including an engine ( 2 ), an operating machine ( 3 ) driven by the engine ( 2 ), and an operation box ( 5 ) housing a controller for the operating machine ( 3 ), comprising a fan ( 2   a ) for cooling the engine ( 2 ) and the operating machine ( 3 ), wherein the operation box ( 5 ) has an upper opening ( 33 ) for taking outside air, which is provided in an upper part of the operation box ( 5 ), and a lower opening ( 32 ) for exhausting air to the outside, which is provided in a bottom part of the operation box ( 5 ), and the lower opening ( 32 ) in the operation box ( 5 ) is disposed so as to be oriented to a flow of cooling air generated by the fan ( 2   a ). 
         [0012]    The second feature of the present invention is that the fan ( 2   a ) is provided on the engine ( 2 ) side in the operating machine ( 3 ), the engine ( 2 ) has an air intake port ( 20 ) for taking air outside of the engine ( 3 ) by rotation of the fan ( 2   a ), the operation box ( 5 ) has a bottom plate ( 16   a ) disposed obliquely to an outer face of the air intake port ( 20 ) of the engine ( 2 ), and the lower opening ( 32 ) is opened in the bottom plate ( 16   a ) so as to directly face from obliquely upward the outer face of the air intake port ( 20 ). 
         [0013]    The third feature of the present invention is that the operation box ( 5 ) further comprises a top plate ( 16   e ) and vertical plates ( 16   b ,  16   c , and  16   d ) vertically joined to the bottom plate ( 16   a ), and the upper opening ( 33 ) is formed in any of the top plate ( 16   e ) and an upper part of the vertical plates ( 16   b ,  16   c , and  16   d ). 
         [0014]    The fourth feature of the present invention is that the lower opening ( 32 ) includes a plurality of long holes ( 32   a ) and blinds ( 32   b ) each projected from an upper end of the long hole ( 32   a ) to the front face of the long hole ( 32   a ). 
       Advantageous Effects of Invention 
       [0015]    According to the present invention having the above-described features, since an opening is provided in each of an upper part of an operation box and a bottom plate, by the flow of cooling air generated by a cooling fan, the flow of air from the upper opening to the lower opening is generated in the operation box. All of parts housed in the operation box are cooled by the flow of air generated by forced convection, not natural convection. 
         [0016]    According to the present invention having the second characteristic, the bottom plate in which the lower opening is formed is not orthogonal to the flow of air which flows in the air intake port of the engine but obliquely crosses the air flow. Therefore, the action of discharging air to the outside works more in the operation box, the flow rate of air generated in the operation box is further increased, and a high cooling effect can be obtained. 
         [0017]    According to the present invention having the third characteristic, an upper opening is formed in the top plate of the operation box. Consequently, the cooling air can be circulated in a region lower than the top plate, that is, in the entire operation box. 
         [0018]    According to the present invention having the fourth characteristic, the blind prevents intrusion of water and dusts from the lower opening as the air exhaust port to the inside of the operation box. 
     
    
     
       BRIEF DESCRIPTION OF DRAWINGS 
         [0019]      FIG. 1  is an oblique perspective figure of the engine generator according to the one embodiment of the present invention. 
           [0020]      FIG. 2  is a left side elevation view of the engine generator according to the one embodiment of the present invention. 
           [0021]      FIG. 3  is a left rearward perspective view of the engine generator according to the one embodiment of the present invention. 
           [0022]      FIG. 4  is a front view of the case constituting the operating box of the engine generator. 
           [0023]      FIG. 5  is a cross section taken along line A-A of  FIG. 4 . 
           [0024]      FIG. 6  is a bottom view of the case constituting the operation box of the engine generator. 
           [0025]      FIG. 7  is a back side view of the operation panel. 
           [0026]      FIG. 8  is a right side elevation view of the operating panel. 
           [0027]      FIG. 9  is a cross section taken along line B-B of  FIG. 6 . 
           [0028]      FIG. 10  is a schematic diagram of the engine generator for explaining the flow of cooling air. 
       
    
    
     DESCRIPTION OF EMBODIMENTS 
       [0029]    Hereinafter, an embodiment of the present invention will be described with reference to the drawings.  FIG. 1  is a perspective view of an engine generator as an engine operating machine according to the embodiment of the present invention.  FIG. 2  is a side view of the engine generator. In  FIGS. 1 and 2 , an engine generator  1  has an engine  2  and a generator  3  driven by the engine  2 . Hereinafter, the engine  2  and the generator  3  will be collectively called a generator body  4 . In the engine generator  1 , the side on which the engine  2  in the generator body  4  is disposed is called a front side, and the side on which the generator  3  is disposed is called a rear side. 
         [0030]    The generator body  4  is surrounded by an external frame  7 . The external frame  7  includes a main frame  8  made of a steel pipe, lower beams  9  coupling lower parts of the main frame  8  in the horizontal direction, two upper beams  10  coupling upper parts of the main frame  8  in the longitudinal direction, and perpendicular beams  11  each downwardly extending from an intermediate part in the longitudinal direction of the upper beam  10  and coupled to the lower part of the main frame  8 . The two lower beams  9  are provided at an interval in the longitudinal direction, one upper beam  10  is provided on the right side, the other upper beam  10  is provided on the left side, one perpendicular beam  11  is provided on the right side, and the other perpendicular beam  11  is provided on the left side. That is, a pair of the upper beam  10  and the perpendicular beam  11  is provided on each of the right and left sides. Although only the upper beam  10  and the perpendicular beam  11  positioned on the left side of the generator  3  are shown, the upper beam  10  and the perpendicular beam  11  on the right side are also provided in similar positions. 
         [0031]    A fuel tank  6  is formed so as to widely cover the entire upper part of the generator body  4 , assures large capacity, and also acts as a generator body cover which suppresses falling of water and dust from above to the generator body  4 . Two lateral pipes  12  whose both ends are coupled to the right and left upper beams  10  are provided in the lateral direction over the fuel bank  6 . The two lateral pipes  12  are coupled to each other by a bracket  13 , and a ring  14  is joined to the bracket  13 . 
         [0032]    There is provided a muffler  17  coupled to an exhaust pipe led between the engine  2  and the generator  3  and extending in the longitudinal direction above the left side of the generator  3 . The generator body  4  is mounted in the external frame  7  by mount devices  90  with buffer members fixed in four places of front, rear, right, and left places on the lower beams  9  and  9 . The mount device  90  has a buffer member (made of, for example, rubber) so that the generator body  4  can displace within a predetermined range in the horizontal and vertical directions, and can absorb vibrations accompanying operation. 
         [0033]    The engine  2  is an air-cooled four-cycle engine and is cooled by outside air taken from an air intake port  20  provided on the front side of the engine  2 . On the rear side or the back side of the air intake port  20 , a fan  2   a  for cooling (to be described later with reference to  FIG. 10 ) which is coupled to the engine  2  and is rotated is provided. By the rotation of the fan  2   a , flows F 1  and F 2  of air taken in the engine  2  are generated. The fan for cooling may be provided not only for the engine  2  but also the generator  3 . 
         [0034]    An operation box  5  for operating the working of the engine generator  1  is provided adjacent to the engine  2  and above the front side of the air intake port  20 , and the fuel tank  6  is provided behind the operation box  5 . The operation box  5  has an operation panel  15  and a case  16  existing on the back side of the operation panel  15  and housing parts for various controls including an automatic voltage regulator (AVR) and electric wires. In the operation panel  15 , a choke button  151 , an engine switch  152 , a breaker switch  153 , a liquid crystal monitor  154 , a plurality of outlets  155 , an earth terminal  156 , and the like are disposed. 
         [0035]    Since particularly the flow F 1  in the flows F 1  and F 2  of air taken in the engine  2  is along the case  16  of the operation box  5 , the pressure in the outer periphery of the case  16 , particularly, around the lower part is lower than that in the upper part of the case  16  where there is no flow of air. Therefore, by providing an opening in each of a bottom plate  16   a  of the case  16  and an upper part (an extension plate  15   a  which is joined to the upper part of the operation panel  15 ), flow of air exhausted from the opening in the lower part of the case  16  to the outside is generated and, accompanying the flow of air, fresh air is taken from the opening in the upper part to the inside of the case  16 . Such a flow of air is continued during the operation of the engine  2 , and the inside of the case  16  of the operation box  5  is forcibly cooled by air. 
         [0036]    In the specification, “upper part” of the case  16  or the operation box  5  refers to a part upper than the center of width in the vertical direction of a member disposed in the uppermost part among members housed in the operation box  5 , for example, refers to a part upper than the center of width in the vertical direction of an AVR  30  (refer to  FIG. 3 ). Preferably, the “upper part” is a region corresponding to the part of upper 20% of the volume of the case  16 . When an upper opening is set in a region lower than the region, all of members in the operation box  5  cannot be effectively cooled. 
         [0037]    Particularly, in the operation box  5  shown in  FIG. 2 , the bottom plate  16   a  of the case  16  is disposed not perpendicular to the rear face (vertical wall) of the case  16  (that is, not as a horizontal face) but disposed, as a tilted face whose front side is low and whose rear side is high, obliquely facing also the air intake port  20 . Consequently, the flow rate of the air F 1  flowing along the bottom plate  16   a  becomes higher, and the pressure difference between the periphery of the lower part of the case  16  and the upper part of the case  16  can be further increased. Although it is preferable to dispose the bottom plate  16   a  so as to obliquely face the air intake port  20 , the bottom plate  16   a  is not limited to the oblique posture but may be perpendicular to the air intake port  20 . 
         [0038]      FIG. 3  is a rearward perspective view of the operation box  5 . In the front part of the operation box  5 , that is, on the rear face of the operation panel  15 , bodies (parts on the rear face side)  161 ,  162 ,  163 ,  164 ,  165 , and  166  of the choke button  151 , the engine switch  152 , the breaker switch  153 , the liquid crystal monitor  154 , the outlets  155 , and the earth terminal  156 , respectively, are attached. The AVR  30  is attached to the rear face of the operation panel  15 , electric wires connected to the body parts of the AVR  30  and switches and the like in the case  16  are lumped together as a harness  31  which is led to the outside via a grommet  45  fit in a harness hole (which will be described later) formed in the rear face of the case  16 . 
         [0039]    Exhaust ports  32  as a plurality of elongated openings (refer to  FIG. 9 ) are formed in the under face of the case  16 . On the other hand, in the extension plate  15   a  joined to the upper part of the operation panel  15 , a plurality of openings are provided as intake ports  33  in proximity to the AVR  30 . The extension plate  15   a  faces an upper rim  15   b  formed by bending an upper part of the operation panel  15 , and the intake ports  33  are disposed in positions facing the space between the rear face of the upper rim  15   b  and the extension plate  15   a.    
         [0040]      FIG. 4  is a front view of the case  16  (view from the operation panel  15  side),  FIG. 5  is a cross section taken along line A-A of  FIG. 4 , and  FIG. 6  is a bottom view of the case  16 . In  FIGS. 4 to 6 , the case  16  has the lower plate (bottom plate)  16   a , right and left walls  16   c  and  16   b , a perpendicular wall (vertical plate)  16   d , and a top plate (ceiling)  16   e , and has a box shape whose face on the side to which the operation panel  15  is attached is open. 
         [0041]    Fitting flanges  16   g  and  16   f  are formed in the right and left walls  16   c  and  16   b . Nuts  42  and  43  are aligned and welded in holes  40  and  41  in a number of fitting holes formed in the flanges  16   g  and  16   f . Bolts (not shown) are fit from the operation panel  15  side into the holes  40  and  41  and screwed in the nuts  42  and  43 . 
         [0042]    In the bottom plate  16   a  which is set obliquely to the perpendicular wall  16   d , the exhaust ports  32  described above with reference to  FIG. 3  are opened. Near the upper corner of the perpendicular wall  16   d , the grommet hole  34  in which the grommet  45  is to be fit is opened. The flanges  16   f  and  16   g  are not extended to a range  35  between the upper end of the flanges  16   f  and  16   g  and the top plate  16   e . In a part to where the flanges  16   f  and  16   g  are not extended, a gap may exist between the operation panel  15  and the case  16  when the case  16  is combined to the operation panel  15 . Then, both ends of the extension plate  15   a  joined to the upper part of the operation panel  15  can be fit in the gap. 
         [0043]      FIG. 7  is a front view of the operation panel  15  (view from the case  16  side), and  FIG. 8  is a side view of the operation panel  15 . In  FIGS. 7 and 8 , upper and lower parts of the operation panel  15  are bent to form an upper rim  15   b  and a lower rim  15   c  projected to the operation face side (surface side). To the operation panel  15 , the extension plate  15   a  is joined so as to cover a part opposite to the operation face, of the upper rim  15   b , that is, the space on the rear side of the upper rim  15   b . In the extension plate  15   a , the openings as the intake ports  33  described with reference to  FIG. 3  are opened in two places. 
         [0044]    In the operation panel  15 , fitting holes  171 ,  172 ,  173 ,  174 ,  175 , and  176  for attaching the bodies  161 ,  162 ,  163 ,  164 ,  165 , and  166  of the choke button  151 , the engine switch  152 , the breaker switch  153 , the liquid crystal monitor  154 , the outlets  155 , and the earth terminal  156 , respectively, are opened. 
         [0045]      FIG. 9  is a cross section taken along line B-B of  FIG. 6 . In  FIG. 9 , in the exhaust port  32  as the lower opening, a plurality of long holes  32   a  is opened. The front face of each of the long holes  32   a  is provided with a blind  32   b  projecting from the upper end of the long holes  32   a  and extending almost perpendicularly from the bottom plate  16   a . The blinds  32   b  play the role of preventing intrusion of water and dusts from above to the operation box  5  through the long holes  32   a . The blinds  32   b  can be formed integrally so as to be projected from the bottom plate  16   a  at the time of forming the long holes  32   a  by embossing. 
         [0046]      FIG. 10  is a schematic diagram of the engine generator for explaining the flow of cooling air. In  FIG. 10 , the outside air is taken in the engine  2  by the cooling fan  2   a  of the engine  2 . The flow F of the air which cooled the engine  2  is taken in the generator  3  by the other cooling fan  3   a  provided on the generator  3  side, passes through the generator  3 , and is exhausted to the outside. 
         [0047]    By the flow F, the air flows F 1  and F 2  are generated on the front side of the engine  2 . By the air flows F 1  and F 2 , negative pressure is generated on the outside of the bottom plate  16   a  of the case  16 . Consequently, air is exhausted from the exhaust ports  32  in the case  16  and air flows in the case  16  from the intake ports  33 . That is, a flow F 3  of air vertically flowing in the operation box  5  is generated so that the operation box  5  is forcibly ventilated and cooled. 
         [0048]    Although the present invention has been described by the embodiment, the invention is not limited to the embodiment and modification is possible on the basis of the matters described in the scope of claims for patent and known techniques. For example, the present invention is not limited to an engine generator but can be widely applied to an engine operating machine driven by an engine. Examples of the engine operating machine include not only a power generator but also a water pump driven by an engine and a high-pressure washing machine for pressure-feeding water by a water pump. 
         [0049]    Although the intake port  33  is formed in the upper part of the operation panel  15 , in place of the intake port  33 , an opening may be formed in the top plate  16   e  of the case  16 . In short, it is sufficient to form an opening in the upper part of the operation box  5  so that outside air is taken in the operation box  5  (the space surrounded by the operation panel  15  and the case  16 ) from a part close to the uppermost part of the operation box  5 . In other words, as long as the intake port  33  is disposed upper than the components such as the AVR  30  and the harness  31  housed in the operation box  5 , an effect that all of the components of the operation box  5  can be cooled by the air flow F 3  is obtained. 
         [0050]    Although the exhaust port  32  in the operation box  5  is disposed so as to face the air intake port  20  of the engine  2 , the exhaust port  32  does not always have to face the air intake port  20  of the engine  2  but may open at least toward the flow of air generated by the cooling fan. Although  FIG. 10  shows the example that the cooling fan is provided for each of the engine  2  and the generator  3 , a cooling fan may be provided for only one of the engine  2  and the generator  3 . 
       REFERENCE SIGNS LIST 
       [0000]    
       
         
           
               1  . . . engine generator 
               2  . . . engine 
               3  . . . generator 
               4  . . . generator body 
               5  . . . operation box 
               6  . . . fuel tank 
               7  . . . external frame 
               15  . . . operation panel 
               16  . . . case 
               20  . . . air intake port 
               32  . . . exhaust port 
               33  . . . intake ports