Abstract:
A small and lightweight sound-proof generator exhibiting sufficient cooling effect. An inverter ( 19 ), an engine fan ( 32 ), a power generating body ( 33 ), an engine ( 34 ), a recoil fan ( 61 ), a recoil starter ( 63 ) are coaxially arranged sequentially from a first inlet port side. A first cooling air passage for cooling inverter ( 19 ), the power generating body ( 33 ), and the engine ( 34 ) with cooling air sucked by the engine fan ( 32 ) from the inlet port ( 21 ), and second and third cooling air passage for cooling a space surrounded by an inverter containing box ( 20 ), an engine fan cover ( 31 ), an engine cover ( 36 ) and a muffler cover ( 52 ) and a soundproof case with cooling air sucked by the recoil fan ( 61 ) from inlet ports ( 21   b   1 ) and ( 21   b   2 ) are formed. Cooling air passed through the first cooling air passage and cooling air passed through the second and the third cooling air passages are merged and discharged from an outlet port after cooling a muffler.

Description:
REFERENCE TO RELATED APPLICATIONS 
       [0001]    This application is a national stage application under 35 USC 371 of International Application No. PCT/JP2006/318682, filed Sep. 14, 2006, the contents of which are incorporated herein by reference. 
     
    
     FIELD OF THE INVENTION  
       [0002]    The present invention relates to a compact and lightweight soundproof type engine generator which is covered with a soundproof case. 
       BACKGROUND OF THE INVENTION  
       [0003]    An engine generator, which is an integrated system of a compact engine and an alternator driven by this engine, is highly portable, and thus suitable for use in urban areas. When intended to be used in an urban area, especially at night, this engine generator has to have a structure in which the entire system is covered with a soundproof case so as to suppress driving noise thereof as far as possible in consideration of an ambient environment. To further suppress leakage of the driving noise, it is necessary to reduce an opening area of the soundproof case as far as possible. At the same time, since an air cooled engine using no cooling water is employed in such an engine generator, securing cooling air to be supplied into the soundproof case is more critical. 
         [0004]    However, reduction of the opening area of the soundproof case causes decrease in an intake and a discharge of cooling air supplied into the soundproof case, whereby the engine overheats to be disabled to operate. Conversely, increasing the opening area deteriorates a soundproofing effect. On the other hand, downsizing the soundproof case makes an air passage therein narrower, so that the air passage is deteriorated in ventilation performance, and thus is not expected to exert a sufficient cooling effect. For these reasons, it is inevitable to confront the reality that convenience in portability, reduction in weight, and reduction in size, which are required of a soundproof type generator, are difficult to achieve. 
         [0005]    The invention disclosed in Japanese Patent Application Publication No. Hei 11-200861 relates to a generator obtained by housing an engine and a alternator in a soundproof case provided with an air inlet for intake of external air. A recoil starter, an engine fan, the alternator, the engine and a muffler, which are arranged in that order, are enclosed with a cylindrical cover, and cooling air is discharged from the air outlet provided to the soundproof case. The air inlet is provided to a side face of the soundproof case, the side face corresponding to a side face of an inverter unit. 
         [0006]    However, in the invention disclosed in Japanese Patent Application Publication No. Hei 11-200861, the recoil starter is arranged in front of the engine fan, which serves as an obstacle against air intake to prevent effective cooling of the alternator and the engine. 
         [0007]    Additionally, the invention employs a structure in which the inverter unit and a fuel tank are provided outside the cylindrical cover, and external air coming in from an air inlet passes along the side face of the inverter unit, then is sucked by the engine fan, and passes through the cylindrical cover. For this reason, cooling of the inverter unit and the fuel tank tends to be insufficient in this structure. 
         [0008]    Furthermore, the cylindrical cover, which covers the engine fan, the alternator, the engine and the muffler, has the recoil starter fixed thereto. Accordingly, a reaction force of starting torque is acted on the cylindrical cover, and thus strength and rigidity are required of the cylindrical cover, which eliminates any choice but to form the cylindrical cover with a pressed sheet metal part, an aluminum cast or the like. This leads to a heavier weight of the engine generator, and makes weight reduction thereof difficult. 
       SUMMARY OF THE INVENTION  
       [0009]    The present invention is a soundproof type engine generator in which an inverter, an engine fan, a alternator, an engine, a recoil fan, and a recoil starter are coaxially arranged in that order from nearest to farthest from a first air inlet. The present invention is characterized in that: a first cooling air passage is formed to allow cooling air sucked by the engine fan from the first air inlet to cool the inverter, the alternator and the engine, second and third cooling air passages are formed to allow cooling air sucked by the recoil fan from second and third air inlets to cool a space surrounded by an inverter housing box, an engine fan cover and a muffler cover, and a soundproof case, and the cooling air having passed through the first cooling air passage and the second and third cooling air passage further cools a muffler, and is then discharged from an air outlet. 
         [0010]    Additionally, the present invention is characterized in that: the second cooling air passage allows cooling air sucked by the recoil fan from the second air inlet to cool a front-face side of a fuel tank, and a back face of an operation panel, the third cooling air passage allows cooling air sucked by the recoil fan from the third air inlet to cool a back-face side of a fuel tank, a carburetor of the engine and a throttle driving motor fixed to an upper part of the carburetor. 
         [0011]    Furthermore, the present invention is characterized in that the muffler is arranged over the recoil starter. 
         [0012]    Furthermore, the present invention is characterized in that the inverter housing box, the engine fan cover and the engine cover are coupled to the engine fan cover, the engine cover and an air discharging duct with sealing members interposed therebetween, respectively. 
         [0013]    Furthermore, the present invention is characterized in that the engine fan cover and the engine cover are fixed to the engine with sealing members interposed therebetween. 
         [0014]    Furthermore, the present invention is characterized in that the engine fan cover is made of a resin. 
         [0015]    Furthermore, the present invention is characterized in that a front-face cover of and a back-face cover of the soundproof case, and the engine cover are, made of a resin. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS  
         [0016]      FIG. 1  is a perspective view showing an external appearance of a soundproof type engine generator according to the present invention; 
           [0017]      FIG. 2  is a cross-sectional view showing an internal structure of the soundproof type engine generator according to the present invention; 
           [0018]      FIG. 3  is an exploded view showing cooling air passages of the soundproof type engine generator according to the present invention; 
           [0019]      FIG. 4  is an exploded view showing a first cooling air passage of the soundproof type engine generator according to the present invention; 
           [0020]      FIG. 5  is a cross-sectional view showing a cooling air passage, which starts from a second air inlet, forming a second cooling air passage of the soundproof type engine generator according to the present invention; 
           [0021]      FIG. 6  is a cross-sectional view showing a cooling air passage, which starts from a third air inlet, forming a third cooling air passage of the soundproof type engine generator according to the present invention. 
       
    
    
     DETAILED DESCRIPTION OF THE INVENTION  
       [0022]    Description will be given of a perspective view, shown in  FIG. 1 , of a soundproof type engine generator  1  according to the present invention. Although an engine, a alternator and the like are covered by a soundproof case and cannot be seen, this configuration enhances a soundproof effect. The soundproof case is composed of a main frame  11 , a left-side face cover  12 , a front-face cover  13 , a right-side face cover  15  (refer to  FIG. 3 ) and a back-face cover  14  (refer to  FIG. 3 ), the right-side face cover  15  and the back-face cover  14  existing behind the view. 
         [0023]    In the left-hand side of the main frame  11 , an air inlet  22   b   1  and an air inlet  22   b   2  are provided which form a second cooling air passage and a third cooling air passage, respectively. In an upper part of the main frame, there is a fuel tank cap  25 , from which fuel is fed. 
         [0024]    In the left-side face cover  12 , a first air inlet  21  which forms a first cooling air passage is provided. 
         [0025]    Through an opening of the front-face cover  13 , there appear: a control panel  18  installed in the mainframe  11 ; and a recoil starter handle  65  by which the soundproof type engine generator  1  is started up. 
         [0026]    The front-face cover  13  and the back-face cover  14  are both made of resin, whereby weight reduction is intended. 
         [0027]    Wheels  17  are provided to four corners of a lower part of the soundproof type engine generator  1 , whereby the soundproof type engine generator  1  can be effortlessly moved. 
         [0028]    Next, with reference to  FIG. 2 , description will be given of a schematic structure of the soundproof type engine generator  1  according to the present invention.  FIG. 2  is a cross-sectional view showing an internal structure of the soundproof type engine generator  1  according to the present invention. 
         [0029]    On a base  16  in the lower part of the soundproof type engine generator  1 , there are coaxially arranged in the following order from nearest to furthest from the first air inlet  21 : an inverter  19 ; an engine fan  32 ; a alternator  33 ; an engine  34  (refer to  FIG. 4 ) covered by engine covers  36   a,    36   b  and  36   c  (refer to  FIG. 4 ); a recoil fan  61  covered by an air discharging duct  38 ; and a recoil starter  63 . Shafts of the engine fan  32 , of a rotor of the alternator  33 , of the engine  34 , of the recoil fan  61 , and of a starter pulley  62  which is a constituent of the recoil starter  63  are coupled to one another. 
         [0030]    The inverter  19  is installed inside an inverter housing box  20 . There is the air inlet  21  in front of the inverter  19 , and the inverter  19  is cooled directly by cooling air thereof. Here, this inverter  19  converts, into a direct-current voltage, an alternating-current voltage generated by the alternator  33 . 
         [0031]    The engine fan  32  and the alternator  33  are installed in an engine fan cover  31  located in back of the inverter housing box  20 . The engine fan  32  is coupled to the rotor of the alternator  33  located in back thereof. The rotor of the alternator  33  has a shaft at the center thereof, thereby being coupled to a crankshaft of the engine  34 . The engine fan  32  rotates with the engine  34  being driven, and sucks cooling air from the first air inlet  21 . Likewise, the rotor of the alternator  33  rotates with the engine  34  being driven, and generates an alternating-current voltage. 
         [0032]    Since the recoil starter  63  is arranged in back of the engine  34 , the engine fan cover  31  is not subjected to a reaction force of starting torque. Consequently, the fan cover  31  does not require strength and rigidity, and is therefore made of resin. By having the fan cover  31  made of resin, weight reduction of the soundproof type engine generator  1  is achieved. 
         [0033]    The engine  34  is covered by the engine covers  36   a,    36   b  and  36   c.  These engine covers  36   a,    36   b  and  36   c  form a cooling passage, and, at the same time, is effective in suppressing driving noise. Here, fuel fed from a fuel tank  24  via a carburetor  66  (refer to  FIG. 6 ) is burnt, thereby causing the crankshaft of the engine  34  to rotate, and causing the engine fan  32  and the rotor of the alternator  33  to rotate. Additionally, the crankshaft of the engine  34  is coupled also to the recoil fan  61  and the starter pulley  62  being a constituent of the recoil starter  63 , which are located in back of the engine  34 , and thereby causes the recoil fan  61  to rotate. 
         [0034]    As will be described later, since the inside of the soundproof case can be efficiently cooled by the second and third cooling air passages, the front-face cover  13  (refer to  FIG. 3 ) and the back-face cover  14  (refer to  FIG. 3 ) of the soundproof case, and the engine covers  36   a,    36   b  and  36   c  are made of resin, whereby weight reduction of the soundproof type engine generator  1  is achieved. 
         [0035]    A front part of the engine fan cover  31  covering the engine fan  32  and the alternator  33 , and a rear part of the inverter housing box  20  are connected to each other with a sealing member  26  interposed therebetween, which restrains air inside the soundproof case from being sucked through an interstice between the engine fan cover  31  and the inverter housing box  20 . 
         [0036]    Additionally, a rear part of the engine fan cover  31  is connected to each of the engine covers  36   a,    36   b  and  36   c  covering the engine  34 , and a sealing member is interposed therebetween, which restrains air from leaking into the soundproof case, the air having cooled the inverter  19  and the alternator  33 . 
         [0037]    A rear part of each of the engine covers  36   a,    36   b  and  36   c  is connected to the air discharging duct  38  with a sealing member (an illustration of which is omitted) interposed therebetween, whereby air having cooled the engine  34  is guided to the air discharging duct  38  without leaking into the soundproof case. 
         [0038]    The recoil fan  61  is located in back of the engine  34 , and in front of the recoil starter  63 , and is arranged inside the air discharging duct  38 . The recoil fan  61  coupled to the crankshaft of the engine  34  rotates with the engine  34  being driven. With the rotation of the recoil fan  61 , cooling air sucked in from the second air inlet  22   b   1  and the third air inlet  22   b   2  is sucked into the inside of the air discharging duct  38  through recoil air inlets  64  provided in the recoil starter  63 . 
         [0039]    The starter pulley  62  which is a constituent of the recoil starter  63  is arranged in back of the recoil fan  61 , and is coupled to the crankshaft of the engine  34 . The recoil starter  63  has a reel (an illustration of which is omitted) housed in the inside thereof, and a cord (an illustration of which is omitted) wound around the reel and the recoil starter handle  65  (refer to  FIG. 3 ) are connected to each other. By pulling out the cord by use of the recoil starter handle  65 , the reel is coupled to the starter pulley  62 , the crankshaft of the engine  34  is caused to rotate, and the engine  34  is started up. After the cord is pulled out, the cord is stored inside the recoil starter  63  by means of a reel winding-back mechanism such as a spring. The coupling between the starter pulley  62  and the reel is cut off after the startup of the engine. 
         [0040]    A muffler  51  is covered by a muffler cover  52 , and is arranged over the recoil starter  63 . This muffler  51  is connected to the engine  34 , and combustion gas generated with the engine  34  being driven passes through the muffler  51  and is discharged, along with cooling air, to the outside of the soundproof case through an air outlet  23 . 
         [0041]    By having the muffler  51  arranged over the recoil starter  63 , space inside the soundproof case can be effectively utilized, whereby downsizing of the soundproof type engine generator  1  is achieved. Furthermore, since the muffler  51  is arranged over the recoil fan  61  while the recoil fan  61  is housed inside the air discharging duct  38  connected to the engine  34  and the recoil starter  63 , cooling air can be effectively collected, and efficiently cools the muffler  51 . 
         [0042]    The fuel tank  24  is installed in an upper left part of the inside of the soundproof case so as to be suspended from the main frame  11 . 
         [0043]    With reference to  FIG. 3 , description will be given of an overview of the cooling air passages according to the present invention. Here, the description will be given with: the first cooling air passage, through which cooling air sucked from the first air inlet  21  flows, being referred to as a cooling air passage A; the second cooling air passage, through which cooling air sucked from the second air inlet  22   b   1  flows, being referred to as a cooling air passage B 1 ; and the third cooling air passage, through which cooling air sucked from the third air inlet  22   b   2  flows, being referred to as a cooling air passage B 2 . 
         [0044]    First of all, description will be given of an overview of the cooling air passage A. 
         [0045]    The engine  34  (refer to  FIG. 4 ) is started up with the recoil starter handle  65  being pulled. The engine fan  32  rotates with the engine  34  being driven, and sucks cooling air from the first air inlet  21  provided in the left-side face cover  12 , thereby cooling the inverter  19  housed in the inverter housing box  20 . The cooling air runs into cooling fins on a front face of the inverter  19 , and then, after cooling the inverter  19 , is sucked into the engine fan cover  31  while flowing around upper and lower parts of the inverter  19 . Since the rear part of the inverter housing box  20  and the front part of the engine fan cover  31  are tightly attached to each other with the sealing member  26  (refer to  FIG. 2 ) interposed therebetween, air inside the soundproof case cannot be sucked into, but only external air having sucked from the air inlet  21  is sucked into the engine fan cover  31 . 
         [0046]    The cooling air cools the alternator  33  (refer to  FIG. 4 ) inside the engine fan cover  31 , and then, after being fed into the engine covers  36   a,    36   b  and  36   c,  cools the engine  34 . The air having cooled the engine  34  is fed into the air discharging duct  38 . While the engine fan cover  31 , and the engine covers  36   a,    36   b  and  36   c  are fixed to the engine  34  with sealing members interposed therebetween, the engine fan cover  31  and the engine covers  36   a,    36   b  and  36   c  are coupled to one another with the sealing members (an illustration of which is omitted) interposed therebetween. Thereby, the cooling air is prevented from being discharged into the soundproof case. However, in order to efficiently cool a throttle driving motor (an illustration of which is omitted) fixed to the carburetor  66  (refer to  FIG. 6 ), the sealing member between the engine  34  and the engine fan cover  31  is partially removed in the neighborhoods of the carburetor  66 , whereby air around the throttle driving motor is convected. Since each of the engine covers  36   a,    36   b  and  36   c  and the air charging duct  38  are tightly attached to each other with a sealing member (an illustration of which is omitted) interposed therebetween, the cooling air is fed into the air discharging duct  38  without leaking into the soundproof case. 
         [0047]    Next, description will be given of an overview of the cooling air passage B 1  and the cooling air passage B 2 . 
         [0048]    The recoil fan  61  (refer to  FIG. 2 ) rotates, whereby cooling air is introduced into the soundproof case from the second air inlet  22   b   1  and the third air inlet  22   b   2  which are provided in the left-hand side of the main frame  11 . After cooling a space surrounded by the inverter housing box  20 , the engine fan cover  31 , the engine covers  36   a,    36   b  and  36   c,  the air discharging duct  38  and the muffler cover  52 , and the soundproof case, the thus introduced cooling air is sucked into the recoil air inlet  64  provided in the recoil starter  63 . 
         [0049]    The cooling air passage B 1  mainly cools the front-face side of the fuel tank  24  (refer to  FIG. 2 ) and a back face of the operation panel  18 . 
         [0050]    Additionally, the cooling air passage B 2  mainly cools the back-face side of the fuel tank  24 , the carburetor  66  and the throttle driving motor. 
         [0051]    The cooling air having passed through the respective cooling air passages join together in the engine air discharging duct  38 , and then, after cooling the muffler  51  (refer to  FIG. 2 ) housed inside the muffler cover  52 , is discharged from the air outlet  23  (refer to  FIG. 2 ) provided in the right-hand side of the main frame  11 . 
         [0052]    With reference to  FIG. 4 , detailed description will be given of the cooling air passage A according to the present invention. 
         [0053]    When the engine  34  is started up with the recoil starter handle  65  being pulled, the engine fan  32  coupled to the crankshaft of the engine  34  rotates. As shown in  FIG. 3 , cooling air is sucked in from the first air inlet  21  (refer to  FIG. 3 ) provided in the left-side face cover  12 , and cools the inverter  19  (refer to  FIG. 3 ) housed in the inverter housing box  20  (refer to  FIG. 3 ). The air having cooled the inverter  19  is sucked into the engine fan cover  31 . Since the inverter housing box  20  and the engine fan cover  31  are tightly attached to each other with a sealing member  31  (refer to  FIG. 2 ) interposed therebetween, air inside the soundproof case cannot be sucked into, but only external air having sucked from the air inlet  21  is sucked into the engine fan cover  31 . 
         [0054]    The cooling air having been sucked into the engine fan cover  31  cools the alternator  33 . 
         [0055]    Thereafter, the cooling air cools the engine  34  located in back of the alternator  33 . While the engine fan cover  31 , and the engine covers  36   a,    36   b  and  36   c  are fixed to the engine  34  with sealing members interposed therebetween, the engine fan cover  31  and the engine covers  36   a,    36   b  and  36   c  are coupled to one another with the sealing members (an illustration of which is omitted) interposed therebetween. Thus, leakage of the cooling air is prevented. Consequently, the engine  34  is efficiently cooled by the cooling air having been sucked by the engine fan. 
         [0056]    Note that, in order to efficiently cool the throttle driving motor (an illustration of which is omitted) fixed to the carburetor  66  (refer to  FIG. 6 ), the sealing member between the engine  34  and the engine fan cover  31  is partially removed in the neighborhoods of the carburetor  66 . Although, in this structure, effective cooling of the throttle driving motor is aimed by convecting air by thus removing the sealing members, another structure may be employed where, with sealing members being applied also to these sections, air suction is guided through the third air inlet  22   b   2  (refer to  FIG. 3 ) by means of a duct or the like. 
         [0057]    Additionally, since the engine fan  32  and the alternator  33  being noise sources are surrounded by the engine fan cover  31 , and the engine  34  also being a noise source is surrounded by the engine covers  36   a,    36   b  and  36 , this structure is excellent in soundproofing effect. Furthermore, since these members are surrounded by the main frame  11 , the front-face cover  18 , the left-side face cover  12 , the right-side face cover  15  and the back-face cover  14  (respectively refer to  FIG. 3 ), a double-layered soundproofing structure is formed, and the soundproofing effect is enhanced thereby. 
         [0058]    Each of the engine covers  36   a,    36   b  and  36   c  that cover the engine  34  and the air discharging duct  38  are coupled to each other with the sealing member (an illustration of which is omitted) interposed therebetween, whereby the cooling air having cooled the engine  34  is fed into the air discharging duct  38  through a ventilation hole  40  without leaking into the soundproof case. This cooling air is mixed, in the engine air discharging duct  38 , with the cooling air having passed through the cooling air passage B 1  and the cooling air passage B 2 , and is then fed into the muffler cover  52 . After cooling the muffler  51  housed in the muffler cover  52 , the cooling air is discharged to the outside from the air outlet  23  (refer to  FIG. 2 ) provided in the right-hand side of the main frame  11  (refer to  FIG. 3 ). 
         [0059]    With reference to  FIG. 5 , detailed description will be given of the cooling air passage B 1 . 
         [0060]    With the engine  34  (refer to  FIG. 4 ) being driven, the recoil fan  61  (refer to  FIG. 2 ) coupled to the crankshaft of the engine  34  rotates. When the recoil fan  61  rotates, external air is sucked into the soundproof case from the second air inlet  22   b   1  provided in a front-face side portion of the left-hand side of the main frame  11 . 
         [0061]    Cooling air having been sucked into the soundproof case cools, first of all, the front-face side of the fuel tank  24 , and the back face of the operation panel  18  (refer to  FIG. 3 ) provided in the front-face side of the main frame  11 . 
         [0062]    Then, after cooling surfaces of the engine fan cover  31 , and the engine covers  36   a  and  36   b,  the cooling air is sucked by the recoil air inlet  64  provided in the recoil starter  63 . 
         [0063]    The cooling air having sucked by the recoil air inlet  64  is fed into the air discharging duct  38 . Here, this cooling air is mixed, in the engine air discharging duct  38 , with the cooling air having passed through the cooling air passage A and the cooling air passage B 2 , and is then fed into the muffler cover  52 . After cooling the muffler  51 , the cooling air is discharged to the outside from the air outlet  23  provided in the right-hand side of the main frame  11 . 
         [0064]    Although temperatures of electrical components of the operation panel  18 , and a temperature of the fuel tank  24  rise to some extent because a temperature inside the soundproof case rises due to radiation heat emitted from a surface of the engine  34 , and also due to the cooling air leaking from the neighborhood of the carburetor  66  and coming from the first cooling air passage, the electrical components and the fuel tank  24  are effectively cooled down by the cooling air passage B 1 , and are restrained from rising in temperature. 
         [0065]    With reference to  FIG. 6 , detailed description will be given of the cooling air passage B 2 . 
         [0066]    With the engine  34  (refer to  FIG. 4 ) being driven, the recoil fan  61  (refer to  FIG. 2 ) coupled to the crankshaft of the engine  34  rotates. When the recoil fan  61  rotates, external air is sucked into the soundproof case from the third air inlet  22   b   2  provided in the back-face side portion of the left-hand side of the main frame  11 . 
         [0067]    Cooling air having been sucked into the soundproof case cools, first of all, the back-face side of the fuel tank  24 . 
         [0068]    Then, the cooling air is partially sucked into an air cleaner  37 , and, after cooling the carburetor  66 , a cylinder head  35 , the engine fan cover  31 , and surfaces of the engine covers  36   a  (refer to  FIG. 3) and 36   c,  the cooling air is sucked by the recoil air inlet  64 . 
         [0069]    The cooling air having been sucked by the recoil air inlet  64  is fed into the air discharging duct  38 . Here, this cooling air is mixed, in the engine air discharging duct  38 , with the cooling air having passed through the cooling air passage A and the cooling air passage B 1 , and is then fed into the muffler cover  52 . After cooling the muffler  51  provided inside the muffler cover  52 , the cooling air is discharged to the outside from the air outlet  23  provided in the right-hand side of the main frame  11 . 
         [0070]    Although temperatures of fuel inside the fuel tank  24  and inside the carburetor  66  rise to some extent because a temperature inside the soundproof case rises due to radiation heat emitted from the surface of the engine  34 , and also due to the cooling air leaking from the neighborhood of the carburetor  66  and coming from the first cooling air passage, the fuel inside the fuel tank  24  and inside the carburetor  66  is effectively cooled down by the cooling air passage B 2 , and is restrained from rising in temperature. 
         [0071]    According to the present invention, the recoil starter is arranged in back of the engine, whereby the first cooling air passage for the cooling air sucked by the engine fan is prevented from being blocked, and an efficient cooling effect is achieved with a large amount of cooling air being sucked from the outside. 
         [0072]    Additionally, since an interstice between each adjacent ones of the inverter housing box, the engine fan cover, the engine cover, and the air discharging duct is tightly closed, cooling air sucked by the engine fan cannot leak from the covers, whereby the inverter, the alternator and the engine can be efficiently cooled in sequence. 
         [0073]    Furthermore, a space surrounded by the inverter housing box, the engine fan cover, the engine covers and the muffler cover, and the soundproof case can be cooled by cooling air sucked by the recoil fan. Even the electrical components of the operation panel, the throttle driving motor of the carburetor, and the fuel inside the fuel tank and inside the carburetor, which rise in temperature due to radiation heat and the like, can be cooled, the radiation heat being emitted from the surface of the engine. Thereby, stable fuel supply is possible while heat-attributable breakdowns of the electrical components can be prevented. 
         [0074]    Furthermore, by having the muffler arranged over the recoil starter and over the air discharging duct inside which the cooling air sucked by the engine fan and the recoil fan are mixed, downsizing of the engine generator is achieved through effective utilization of space inside the soundproof case while efficient cooling of the muffler is also possible. 
         [0075]    Furthermore, by having the recoil starter arranged in back of the engine, the engine fan is not subject to the reaction force of starting torque and thereby does not require strength and rigidity. Therefore, the engine fan cover can be made of resin. Consequently, weight reduction is achieved. 
         [0076]    Furthermore, since the inside of the soundproof case can be effectively cooled by having the second and third cooling air passages provided as described above, the front-face cover and back-face cover of the soundproof case, and the engine covers can be made of resin, which also leads to weight reduction of the generator.