Abstract:
A work vehicle has a plurality of wheels including a first wheel and a fuel tank disposed upwardly of the first wheel. The fuel tank includes a first portion which is located higher than the highest point of the first wheel in a side view and which also is overlapped at least partially with the first wheel in a top view; a second portion disposed forwardly of the highest point of the first wheel and extending downwardly from the first portion so as to extend lower than the highest point of the first wheel, the second portion being in fluid communication with the first portion; and a third portion disposed rearwardly of the highest point of the first wheel and extending downwardly from the first portion so as to extend lower than the highest point of the first wheel, the third portion being in fluid communication with the first portion.

Description:
BACKGROUND OF THE INVENTION 
     The present invention relates to a work vehicle having a fuel tank mounted upwardly of a vehicle wheel. 
     As a fuel storing arrangement for use in a work vehicle described above, there is known an arrangement in which a fuel tank is provided with a bulging portion at a front end portion thereof in the fore-aft direction of the vehicle body, the bulging portion bulging downward so as to cover the wheel from above from the front side thereof (see, e.g. JP2004-236641). 
     Recently, there has been a need for increase in the capacity for the fuel tank so as to achieve improvement in working efficiency through reduction in the number of refueling operations required. However, mere capacity enlargement of fuel tank can invite disadvantageous enlargement of the work vehicle. 
     Then, it is conceivable to mount, instead of the fuel tank having the above-described conventional construction, a fuel tank configured to cover the upper side of the wheel from its rear side, through effective utilization of the space available above the wheel (the free space between the wheel and the fender). This construction, however, invites increase in the number of components. And, this also requires the trouble of feeding fuel to each individual fuel tank at the time of fuel replenishment. 
     SUMMARY OF THE INVENTION 
     The object of the present invention is to provide an improved fuel tank. 
     According to one embodiment of the invention, a work vehicle comprises: 
     a plurality of wheels including a first wheel; 
     a fuel tank disposed above the first wheel; 
     wherein the fuel tank includes:
         a first portion which is located higher than the highest point of the first wheel in a side view and which also is overlapped at least partially with the first wheel in a top view;   a second portion disposed forwardly of said highest point of the first wheel and extending downwardly from the first portion so as to extend lower than said highest point of the first wheel, said second portion being in fluid communication with said first portion; and   a third portion disposed rearwardly of said highest point of the first wheel and extending downwardly from the first portion so as to extend lower than said highest point of the first wheel, said third portion being in fluid communication with said first portion.       

     With the above-described characterizing construction, it is possible to increase the capacity of the fuel tank through effective utilization of the space available upwardly of the wheel. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is an overall side view showing a riding vehicle type grass mower, 
         FIG. 2  is a side view of a fuel tank, 
         FIG. 3  is a plan view of the fuel tank, 
         FIG. 4  is a side view in vertical section of the fuel tank, 
         FIG. 5  is a side view in vertical section showing a communicating passway, and 
         FIG. 6  is a side view of a fuel tank according to a further embodiment. 
     
    
    
     DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS 
     Next, the present invention will be described in details by way of an embodiment in which the invention is applied to a riding vehicle type grass mower as one example of a working vehicle. 
       FIG. 1  shows an overall side view of the riding vehicle type grass. As shown in this figure, the riding vehicle type grass mower employed exemplarily in the present embodiment is configured as a mid-mount type wherein between a pair of right and left front wheels  2  and a pair of right and left rear wheels  3  of a traveling vehicle body  1 , there is mounted, via a link mechanism  4 , a mower  5  to be lifted up/down. 
     The traveling vehicle body  1  includes, at a front side thereof, a front frame  6  comprised of angular pipe members or the like. The front frame  6  supports the link mechanism  4  and also mounts the front wheels  2  at the front right and left ends, with the front wheels  2  being steered about respective vertical axes. 
     The front frame  6  includes a boarding step  8  made of a plate metal and configured to cover this frame  6  substantially entirely from above. The link mechanism  4  is operable to lift up/down the mower  5  in parallel in response to an activation of a single-acting type hydraulic cylinder  7 . On the surface of the boarding step  8 , there is laid a rubber mat (not shown). And, at a front center region of the step  8 , there are disposed a brake pedal  9  which is urged to return to its non-braking position and a lock pedal  10  capable of retaining the brake pedal  9  at its braking position against the urging force. Rearwardly and upwardly of the boarding step  8 , there is provided a driver&#39;s seat  11  which is position-adjustable. On the right and left opposed sides of the driver&#39;s seat  11 ′ there are disposed fenders  12  and speed changer levers  13  respectively. Rearwardly of the diver&#39;s seat  11 , there is mounted erect an arch-like protection frame  14 . That is to say, with this riding vehicle type grass mower, there is formed a riding driver&#39;s section  15  on the front side of the traveling vehicle body  1 . 
     At a rear portion of the vehicle body  1 , there is provided a rear frame  1  connected to the rear end of the front frame  6 . This rear frame  6  mounts thereon an air-cooled type gasoline engine  17 . Power from the engine  17  is speed-reduced by a transmission apparatus  18  disposed forwardly and downwardly of the engine  17  and split into a traveling power and a working power. 
     Though not shown, inside the transmission apparatus  18 , there is provided a clutch for allowing/interrupting transmission of the working power. The traveling power from the transmission apparatus  18  is speed-changed by hydrostatic stepless transmission units (referred shortly to as “HST” hereinafter) connected continuously with the right and left sides of the transmission apparatus  18 . The speed-changed power from the respective right/left HST is further speed-reduced by a speed reducing unit connected to the lateral side of the associated HST on the outer side of the vehicle body. Finally, the speed-reduced power from the right/left speed reducing unit is transmitted to the rear wheel  3  attached to and associated with this speed reducing unit. 
     Each one of the right and left HSTs has its speed changer shaft operably coupled with a corresponding speed changer lever  13 , so that the HST may be operated for a speed changing operation in response to a forward or rearward pivotal operation on the speed changer lever  13 . With this, in response to a forward or rearward pivotal operation on the speed changer lever  13 , the HST corresponding to the respective operational lever  13  may be operated for a speed change so as to drive, in a changed-speed, the right or left rear wheel  3  associated therewith independently. 
     That is to say, with this riding vehicle type grass mower, the right and left front wheels  2  can be steered and driven and the right and left rear wheels  3  can be driven in a changed speed independently of each other, so that there can be provided, as desired, one of conditions consisting of a stopped condition with the right and left rear wheels  3  both being stopped, a straight traveling condition with the right and left rear wheels  3  both being driven forwardly or in reverse at an equal speed, a gentle turn condition with the right and left rear wheels  3  being driven forwardly or in reverse at different speeds from each other, a pivot turn condition with one of the right and left rear wheels  3  being stopped and the other thereof being driven forwardly or in reverse, and a spin turn condition with one of the right and left rear wheels  3  being driven forwardly and the other thereof being driven in reverse. 
     As shown in  FIG. 1 , the working power from the transmission apparatus  18  is transmitted via a transmission shaft  19  which is configured to be extendable and contractible and universal joints  20  provided at opposed ends of the transmission shaft  19  to the mower  5 . With this, a constant-speed power can be provided to the mower  5 , regardless of the traveling speed or traveling condition. 
     As shown in  FIGS. 1-3 , upwardly of each one of the right and left rear wheels  3 , there is disposed a fuel tank  21  with utilizing the space formed between the rear wheel  3  and the fender  12  associated therewith. Each fuel tank  21  includes, at a rear upper end portion thereof a fuel filling opening  21 A which is opened/closed by a threaded cap  22 . 
     Each fuel tank  21  is configured as a two-forked shaped construction having, at opposed ends thereof in the fore-and-aft direction of the vehicle body, downwardly bulging portions  21 B,  21 C which bulge downwards, so that the tank  21  “strides over” the rear wheel  2  corresponding thereto in the fore-and-aft direction of the vehicle body. Also, each fuel tank  21  is formed with such an increased width that when this tank is mounted, an inner side portion  21 D thereof located on the lateral side of the vehicle body inner side of the tank  21  may be located on more inner side of the vehicle body than the inner lateral face of the corresponding rear wheel  3 . The inner side portion  21 D of each fuel tank  21  is formed to bulge toward the center of the corresponding rear wheel  3  so that the portion  21 D is overlapped with the outer peripheral portion of the rear wheel  3  in its lateral side view. For each fuel tank  21 , an outer side portion  21 E thereof located immediately above the corresponding rear wheel  3  is configured to have a curved portion  21 F having a bottom face curved along the outer periphery of the corresponding rear wheel  3 . 
     That is to say, the fuel tank  2  formed like a wide two-forked shaped construction and having the inner side portion  21 D bulging toward the center of the rear wheel  3  in order to achieve increase in its capacity, is disposed in an advantageous manner through effective utilization of the space formed between the rear wheel  3  and the fender  12 . 
     As shown in  FIGS. 1-5 , in each fuel tank  21 , in the front side bulging portion  21 B, there are provided a suction pipe  23  for allowing feeding of fuel to the engine  17  and a float type fuel gauge  24 . In the front side bulging portion  21 B, a communicating portion  21 G which projects rearwards is provided in the bottom rear face of the inner side portion  21 D. In the rear side bulging portion  21 C, a communicating portion  21 H which projects forwards is provided in the bottom rear face of the inner side portion  21 D. To these front and rear communicating portions  21 G,  21 H, there is connected a communicating pipe  25  which forms a communicating passway  25 A establishing communication between the portions  21 G,  21 H. The communicating pipe  25  incorporates therein a one-way valve  26  which prevents flow of fuel from the front side communicating portion  21 G (front bulging portion  21 B) to the rear side communicating portion  21 H (rear bulging portion  21 C). 
     With the above arrangement, an amount of fuel stored at the front bulging portion  21 B will flow through the communicating passway  25 A to the rear bulging portion  21 C in the course of hill climbing of the vehicle. As a result, the amounts of fuel stored at the two-forked shaped respective fuel tanks  21  can be effectively fed to the engine  17 , without running out of the fuel. 
     [Other Embodiments] 
     [1] The working vehicle to which the present invention is applied can be a mid-mount mower having a mower  5  mounted between the right and left front wheels  2  and the right and left rear wheels  3  of a four-wheel drive type traveling vehicle body  1 , a front-mount mower having a mower  5  mounted forwardly of the right and left front wheels  2  of the traveling vehicle body, a tractor which allows additional mounting of an implement such as a mower  5 , a riding vehicle type rice planting machine, etc. 
     [2] The fuel tank  21  may be provided only on one of the right and left sides of the traveling vehicle body  1 . 
     [3] The fuel tank  21  may be disposed upwardly of the front wheel  3 . 
     [4] The fuel tank  21  may be configured as a right/left integral type having a communicating portion for establishing communication between right and left fuel tanks (tank portions or halves)  21 . 
     [5] The suction pipe  23  and the fuel gauge  24  may be provided in the rear bulging portion  21 C and the one-way valve  26  for preventing fuel flow from the rear bulging portion  21 C to the front bulging portion  21 B may be provided in the communicating pipe  25  (communicating passway  25 A). 
     [6] The communicating pipe  23  (communicating passway  25 A) may not incorporate the one-way valve  26 . In this construction, reverse flow of fuel may be prevented by providing a height difference between the front and rear bulging portions  21 B,  21 C. 
     [7] As shown in  FIG. 6 , the suction pipe  23  may be provided in each one of the front and rear bulging portions  21 B,  21 C, rather than providing communication between the bottoms of the front and rear bulging portions  21 B,  21 C.