Abstract:
In a work vehicle, because of growing need to equip a DPF for exhaust gas countermeasures near an engine and a request of increasing the size of a fuel tank, a system including the fuel tanks provided below a floor step and on left and right sides of a transmission case has been employed. However, when a lawn mower is installed between front wheels and rear wheels, an increasing width of a vehicle body becomes a problem. 
     To solve the problem, a locus of the raising and lowering operation of a lawn mower  5  is specified by a parallel link formed of left and right front links  43, 43  and left and right mid links  45, 45,  and in a work vehicle where the lawn mower  5  is freely raised and lowered, the left and right mid links  45, 45  are respectively disposed between a transmission case  3  and fuel tanks  16 L,  16 L.

Description:
CROSS REFERENCE TO RELATED APPLICATIONS 
       [0001]    This application claims priority to Japanese Patent Application No. 2013-134417, filed Jun. 27, 2013, the disclosures of which is incorporated herein by reference in its entirety. 
       BACKGROUND 
       [0002]    1. Technical Field 
         [0003]    The present invention relates to a work vehicle, such as a tractor, driven by front wheels and rear wheels and including a work machine, such as a lawn mower, between the front wheels and the rear wheels. 
         [0004]    2. Related Art 
         [0005]    A work vehicle described in JP 2012-70696 A has a pair of front wheels and a pair of rear wheels on a body frame, and includes a lawn mower serving as a work machine between the front wheels and the rear wheels and below a floor step. In the lawn mower, raising and lowering operation is guided by a parallel link formed of a front link (a front link 43 in JP 2012-70696 A) and a mid link (a rear link  45  in JP 2012-70696 A). The lawn mower is raised and lowered with a hydraulic cylinder serving as a driving source. 
         [0006]    Further, the work vehicle includes an engine at a front part. Power from the engine is transmitted to the rear wheels provided at the rear part or the work machine by a transmission within a transmission case (e.g., a front transmission case in JP 2012-70696 A) provided below the floor step. 
         [0007]    In a work vehicle, because of growing need to equip a DPF (Diesel particulate filter) for exhaust gas countermeasures in a vicinity of an engine and a request of increase in size of a fuel tank, a system including the fuel tanks below a floor step and on left and right sides of a transmission case has been employed. However, in a case where a work machine, such as a lawn mower, is installed between front wheels and rear wheels, it is necessary that the fuel tank or peripheral equipment thereof should be installed to avoid interference with a parallel link serving as a guide for the work machine. There is a problem in that a width of a vehicle body becomes large. Therefore, a problem to be solved by the present invention is to provide a work vehicle solving the problem. 
       SUMMARY 
       [0008]    In order to solve the above-described problem, a work vehicle in one aspect is provided with a transmission case ( 3 ) configured to be provided at a machine body; fuel tanks ( 16 L,  16 R) configured to be respectively provided on left and right sides with the transmission case ( 3 ) therebetween; a lawn mower ( 5 ) configured to be installed below the transmission case ( 3 ) and between front wheels ( 7 ,  7 ) and rear wheels ( 8 ,  8 ) for driving a vehicle body; and a parallel link formed of left and right front links ( 43 ,  43 ) disposed at a front part of the machine body and left and right mid links ( 45 ,  45 ) disposed at a central part of the machine body and configured to perform raising and lowering operation of the lawn mower ( 5 ), wherein the left and right mid links ( 45 ,  45 ) are respectively disposed between the transmission case ( 3 ) and the fuel tanks ( 16 L,  16 R). 
         [0009]    Further, a second aspect of the present invention is the work vehicle according to the first aspect, wherein engagement parts ( 44 ,  44 ) between the mid links ( 45 ,  45 ) and the vehicle body are disposed above a communication pipe ( 17 ) communicating between the fuel tanks ( 16 L,  16 R). 
         [0010]    Moreover, a third aspect of the present invention is the work vehicle according to the second aspect, wherein a bent part configured to bend downward is provided at the mid links ( 45 ,  45 ), and when the lawn mower ( 5 ) is moved to a lowered position, the mid links ( 45 ,  45 ) and the communication pipe ( 17 ) are not brought into contact with each other. 
         [0011]    Additionally, a fourth aspect of the present invention is the work vehicle according to the third aspect, wherein height regulation stoppers ( 36 ,  36 ) configured to regulate a raising height of the lawn mower ( 5 ) are provided on outer sides of the engagement parts ( 44 ,  44 ). 
         [0012]    According to the first aspect of the present invention, the mid links  45 ,  45  for guiding the raising and lowering operation of the lawn mower  5  are respectively disposed between the transmission case  3  and the fuel tanks  16 L,  16 R. Consequently, expansion of a vehicle body width due to the provision of the fuel tanks  16 L,  16 R can be prevented, and respective components of the transmission case  3 , the fuel tanks  16 L,  16 R, and the parallel link including the mid links  45 ,  45  can be reasonably disposed in a vehicle width direction. Therefore, an overall vehicle body width can be narrowed. 
         [0013]    According to the second aspect of the present invention, in addition to the effect of the invention described in the first aspect, the engagement parts  44 ,  44  between the mid links  45 ,  45  and the vehicle body are disposed above the communication pipe  17  communicating between the fuel tanks  16 L,  16 R. Consequently, while avoiding the contact of the communication pipe  17  installed at a relatively low part between the fuel tanks  16 L,  16 R and the vertically moving mid links  45 ,  45 , respective components of the transmission case  3 , the lawn mower  5 , and the parallel link including the mid links  45 ,  45  can be reasonably disposed in a vehicle height direction. Therefore, an overall vehicle height can be lowered. 
         [0014]    According to the third aspect of the present invention, in addition to the effect of the invention described in the second aspect, the bent part configured to bend downward is provided at the mid links  45 ,  45 . When the lawn mower  5  is moved to the lowered position, the mid links  45 ,  45  and the communication pipe  17  are not brought into contact with each other. Consequently, while a raising and lowering operation stroke needed by the lawn mower  5  is secured, a raising height of the lawn mower  5  can be secured to the maximum. Also, since the bent part is detoured above the communication pipe  17 , a front and rear length of the mid link  45  can be shortened, and it is not necessary to increase an overall length of the work vehicle because of the mid link  45 . According to the fourth aspect of the present invention, in addition to the effect of the invention described in the third aspect, by providing the height regulation stoppers  36 ,  36 , the contact of the fuel tanks  16 L,  16 R and the lawn mower  5  can be prevented. Further, by providing the height regulation stopper  36  on the outer side of the engagement part  44 , a length between the height regulation stoppers  36 ,  36  can be increased. Accordingly, when the lawn mower  5  is brought into contact with the one height regulation stopper  36 , left and right balance is not lost, and it is possible to perform stable operation. Additional objects and advantages of the invention will be set forth in part in the description which follows, and in part will be obvious from the description, or may be learned by practice of the invention. The objects and advantages of the invention will be realized and attained by means of the elements and combinations particularly pointed out in the appended claims. 
         [0015]    It is to be understood that both the foregoing general description and the following detailed description are exemplary and explanatory only and are not restrictive of the invention, as claimed. 
         [0016]    The accompanying drawings, which are incorporated in and constitute a part of this specification, illustrate several embodiments of the invention and together with the description, serve to explain the principles of the invention. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0017]    Reference will now be made to the accompanying drawings which illustrate exemplary embodiments of the present disclosure. In the drawings: 
           [0018]      FIG. 1  is a side view of a work vehicle according to the first embodiment of the present invention; 
           [0019]      FIG. 2  is a plan view of a periphery of a lawn mower of the work vehicle in  FIG. 1 ; 
           [0020]      FIG. 3  is a side view of the periphery of the lawn mower of the work vehicle in  FIG. 1 ; 
           [0021]      FIG. 4  is a front view of the periphery of the lawn mower of the work vehicle in  FIG. 1 ; 
           [0022]      FIG. 5  is a plan view of the lawn mower of the work vehicle in  FIG. 1 ; 
           [0023]      FIG. 6  is a plan view of a periphery of fuel tanks of the work vehicle in  FIG. 1 ; 
           [0024]      FIG. 7  is a front view of the periphery of the fuel tanks of the work vehicle in  FIG. 1 ; 
           [0025]      FIG. 8  is a side view of the periphery of the fuel tanks of the work vehicle in  FIG. 1 ; 
           [0026]      FIG. 9  is a perspective view of the periphery of the fuel tanks of the work vehicle in  FIG. 1 ; 
           [0027]      FIGS. 10A to 10C  are explanatory diagrams of a periphery of an engagement part of the work vehicle in  FIG. 1 ; and 
           [0028]      FIG. 11  is a side view of a work vehicle according to a second embodiment. 
       
    
    
     DESCRIPTION OF EXEMPLARY EMBODIMENTS 
       [0029]    Reference will now be made in detail to several exemplary embodiments of the present disclosure, including those illustrated in the accompanying drawings. Whenever possible, the same reference numbers will be used throughout the drawings to refer to the same or like parts. 
         [0030]    A description will hereinafter be given of embodiments of the present invention in conjunction with drawings. It should be noted that in the present specification, left and right in an advancing direction of a vehicle, on which an operator rides, is respectively referred to as “left” and “right” and that front and rear therein is respectively referred to as “front” and “rear”.  FIG. 1  illustrates a right side view of a tractor serving as a work vehicle according to a first embodiment of the present invention. In the drawing, a cloud-shaped portion perspectively illustrates peripheral members of a lawn mower according to the embodiment of the present invention.  FIG. 2  illustrates a plan view of a periphery of a lawn mower  5  of the work vehicle in  FIG. 1 ,  FIG. 3  illustrates a right side view thereof, and  FIG. 4  illustrates a front view thereof. Further,  FIG. 6  illustrates a plan view of a periphery of fuel tanks  16 L,  16 R of the work vehicle in  FIG. 1 ,  FIG. 7  illustrates a front view thereof,  FIG. 8  illustrates a side view thereof, and  FIG. 9  illustrates a perspective view thereof. 
         [0031]    In the work vehicle according to the embodiment of the present invention, power of an engine  10  mounted within a hood  11  of a vehicle body front part is appropriately subjected to speed change by a speed change device within a transmission case  3 . The power is transmitted to a front wheel shaft  14  and a rear wheel shaft  15 , and drives both a wheel type front wheel  7  and a wheel type rear wheel  8  or only the rear wheel  8 . A rear wheel fender  8   a  for preventing mud from scattering from the rear wheels  8 ,  8  is arranged above each of the rear wheels  8 ,  8  of the work vehicle. In the work vehicle, the engine  10  is mounted to a front part through a body frame  2  supported by a front axle housing  18 , and a clutch housing, the transmission case  3 , and the like are integrally coupled to a rear side of the engine  10 . A rear axle housing  4  is provided at a rearmost part of the transmission case  3 , thereby axially attaching the rear wheel  8  to both left and right side parts. 
         [0032]    A cabin  9  including a floor step  13  is mounted on the body frame  2  of the vehicle. An operator sitting in a driver&#39;s seat  19  provided within the cabin  9  operates an operation handle, such as a steering wheel  12 , erected at a center and travels while steering the front wheel  7 . Also, various types of operation levers and the like for operating and controlling the work vehicle are provided on a side of the driver&#39;s seat  19 . The transmission case  3  is provided below the floor step  13 , and resin fuel tanks  16 L,  16 R are respectively provided on left and right sides with the transmission case  3  therebetween. A communication pipe  17  for communicating the two fuel tanks  16 L,  16 R is provided at a lower part of the fuel tanks  16 L,  16 R in such a way that the both fuel is consumed equally. Further, a hose connects the fuel tanks  16 L,  16 R and the engine  10 , and a pump for supplying the fuel from the fuel tanks  16 L,  16 R to the engine  10  is disposed. Accordingly, the fuel from the fuel tanks  16 L,  16 R provided below the engine  10  is supplied stably. 
         [0033]    In the work vehicle according to the embodiment of the present invention, the lawn mower  5  serving as a work machine is installed below the transmission case  3  and between front and rear of the left and right front wheels  7 ,  7  and the left and right rear wheels  8 ,  8 . The lawn mower  5  is raised and lowered when the operator operates a raising and lowering lever in the driver&#39;s seat  19 , and the power branched from the transmission within the transmission case  3  is transmitted to a PTO shaft  6 . The PTO shaft  6  transmits the power to a mower deck  24  of the mower  5  through a universal joint, and lawn mowing is performed by driving a reaping blade within the lawn mower  5 . 
         [0034]    A support mechanism of the lawn mower  5  will be described. As illustrated in  FIG. 1 , a pair of left and right front links  43 ,  43  is rotatably provided between a front support plate  41  provided at a front end part of the mower deck  24  and a support plate  42  provided at a front end part of the body frame  2  in a suspended state. 
         [0035]    On the other hand, a pair of left and right mid links  45 ,  45  is rotatably provided between a rear end part of the lawn mower  5  and engagement parts  44 ,  44  provided at a front and rear intermediate part of the body frame  2 . A parallel link is constituted of the front link  43  and the mid link  45 . By constituting in this way, a locus of the raising and lowering operation of the lawn mower  5  can be specified while maintaining a posture of the lawn mower  5 . 
         [0036]    In the work vehicle according to the embodiment of the present invention, the mid links  45 ,  45  are respectively disposed between the transmission case  3  and the fuel tanks  16 R,  16 L in a plan view. Further, the engagement parts  44 ,  44  between the mid links  45 ,  45  and the body frame  2  are configured so as to be positioned above the communication pipe  17  communicating between the fuel tanks  16 L,  16 R. Moreover, the mid link  45  has a bent part bending downward and a shape including a “dogleg-shaped” portion in a side view. Additionally, even if the lawn mower  5  is moved to a lowered position, the mid links  45 ,  45  and the communication pipe  17  are not brought into contact with each other. 
         [0037]    The mid links  45 ,  45  for guiding the raising and lowering operation of the lawn mower  5  are respectively disposed between the transmission case  3  and the fuel tanks  16 L,  16 R. In other words, the mid links  45 ,  45  are provided at narrow space parts between the transmission case  3  and the fuel tanks  16 L,  16 R existing in the conventional configuration. Accordingly, expansion of a vehicle body width can be prevented, and respective components of the transmission case  3 , the fuel tanks  16 L,  16 R, and the parallel link including the mid links  45 ,  45  can be reasonably disposed in a vehicle width direction. Therefore, an increase in the overall vehicle body width can be prevented. 
         [0038]    The engagement parts  44 ,  44  between the mid links  45 ,  45  and the vehicle body are disposed above the communication pipe  17  communicating between the fuel tanks  16 L,  16 R. Accordingly, while avoiding the contact of the communication pipe  17  installed at a relatively low part between the fuel tanks  16 L,  16 R and the vertically moving mid links  45 ,  45 , respective components of the transmission case  3 , the lawn mower  5 , and the parallel link including the mid links  45 ,  45  can be reasonably disposed in a vehicle height direction. Therefore, an overall vehicle height can be lowered. 
         [0039]    The bent part bending downward is provided at the mid links  45 ,  45 . When the lawn mower  5  is moved to a raised position, the mid links  45 ,  45  and the communication pipe  17  are not brought into contact with each other. Accordingly, while a raising and lowering operation stroke needed by the lawn mower  5  is secured, a raising height of the lawn mower  5  can be secured to the maximum. Additionally, the bent part bending downward is formed at the mid links  45 ,  45  and connects the mid links  45 ,  45  and the lawn mower  5 . Therefore, a front and rear length of the mid link  45  can be shortened, and there is no need to increase an overall length of the work vehicle because of the mid link  45 . 
         [0040]    Next, description will be given of a lawn mower raising and lowering linkage mechanism  48  serving as a raising and lowering mechanism of the lawn mower  5 . A lower end of the one mid link  45  (left side in the present embodiment) of the left and right mid links  45 ,  45  is extended, and the lawn mower raising and lowering link mechanism  48  is configured between an extension part  45   a  and a lower link  47  provided at a rear part of the work vehicle. The lower link  47  is rotated upward and downward by a hydraulic cylinder (not illustrated) by operating a raising and lowering operation lever  53  at hand. 
         [0041]    The above-described lawn mower raising and lowering linkage mechanism  48  is constituted of a hanging rod  56 , an intermediate link  55 , a traction rod  59 , and a bracket  58 . The hanging rod  56  is provided between the extension part  45   a  of the above mid link  45  and the intermediate link  55 , and is rotatably coupled with these members. The intermediate link  55  is “dog-leg” shaped, and a “dog-shaped” bent part is rotatably coupled to a bracket  49  suspended from the body frame  2  so as to bend upward. The intermediate link  55  is also coupled rotatably to the traction rod  59 . The traction rod  59  is rotatably coupled to the bracket  58  also used for reinforcement. 
         [0042]    With the above-described configuration, when the lawn mower  5  is raised from a working position where mowing operation is performed to a non-working position where the lawn mower  5  is in a stored state, the operator operates the raising and lowering operation lever to a raising side and rotates to raise the lower link  47 . Accordingly, by the lawn mower raising and lowering linkage mechanism  48 , the interlocking mid link  45  is rotated around the engagement part  44 , and the lawn mower  5  is raised while holding its posture. Further, when the lawn mower  5  is lowered from the non-working position to the working position, the operator operates the raising and lowering operation lever to a lowering side and rotates to lower the lower link  47 . Consequently, the lawn mower  5  is lowered by the lawn mower raising and lowering linkage mechanism  48 . 
         [0043]    In addition to  FIGS. 1 to 9 , a periphery of the engagement part  44  between the mid link  45  and the vehicle body will be described referring to  FIGS. 10A to 10C .  FIGS. 10A to 10C  are enlarged views of an “a” part in  FIG. 4 , i.e., the periphery of the engagement part  44  on a vehicle body left side.  FIG. 10A  is a plan view of the “a” part,  FIG. 10B  is a right side view thereof, and  FIG. 10C  is a front view thereof. 
         [0044]    In the work vehicle according to the embodiment of the present invention, left and right side beams  60 ,  60  extending outward are coupled to a front side surface of the transmission case  3 . A vertical bracket  61  suspended downward is provided at the side beam  60 , and further, a stopper supporter  62  for fixing a height regulation stopper  36  is provided at a lower end of the vertical bracket  61 . A front part of the mid link  45  is fixed by welding two steel plates at a predetermined interval in a left and right direction. The vertical bracket  61  is sandwiched by the two plates, and a shaft protruding from a side surface of the vertical bracket  61  is fitted into a hole of the mid link  45 . Accordingly, the mid link  45  is freely rotated around the engagement part  44  with respect to the vehicle body. In a case where the mid link  45  is rotated downward, the mid link  45  and the stopper supporter  62  are brought into contact with each other before the mid link  45  is brought into contact with the communication pipe  17 . Further, a mount rubber is mounted to a hole provided at an upper part of the side beam  60 , and the cabin  9  is provided thereat. A fuel tank support member for providing the fuel tank  16  is fixed by the side beam  60  and a rear side beam  63  provided at a rear side surface of the transmission case  3 . 
         [0045]    In the work vehicle according to the embodiment of the present invention, each of the height regulation stoppers  36 ,  36  regulating the raising height of the lawn mower  5  serving as the work machine is provided at the stopper supporter  62 . The height regulation stopper  36  has a structure in which soft rubber is provided at a lower end of a male screw. The height regulation stopper  36  is installed at the stopper supporter  62  symmetrically provided at each of the side beams  60 ,  60  configuring the body frame  2 . Describing in detail, the left and right height regulation stoppers  36 ,  36  are disposed on rear sides of foremost parts of the fuel tanks  16 L,  16 R, and on further inner sides of inner inward surfaces of the left and right fuel tanks  16 L,  16 R opposing to each other. In the present embodiment, an “inward surface” means a surface facing a left and right center of a plurality of outer peripheral surfaces held by the fuel tanks  16 L,  16 R. The “inward surface” includes not only a surface that is closest to the left and right center of the surfaces facing the left and right center, but also a surface facing the left and right center while forming a recessed part provided at the front parts of the fuel tanks  16 L,  16 R. Further, the left and right height regulation stoppers  36 ,  36  are provided on outer sides of the engagement parts  44 ,  44  serving as rotation coupling parts between the body frame  2  and the mid links  45 ,  45 . 
         [0046]    By providing the height regulation stoppers  36 ,  36 , the contact of the fuel tanks  16 L,  16 R and the lawn mower  5  can be prevented. Further, by disposing the height regulation stoppers  36 ,  36  on the rear sides of the foremost parts of the fuel tanks  16 L,  16 R, and on the further inner sides of the inward surfaces of the fuel tanks  16 L,  16 R, a space part can be effectively utilized. Moreover, since the circumference is protected, a regulating height position of the height regulation stopper  36  is not changed due to age-related deterioration or the like, and the contact can be prevented more reliably. 
         [0047]    By providing the height regulation stoppers  36 ,  36  on the outer sides of the engagement parts  44 ,  44 , a length between the height regulation stoppers  36 ,  36  can be increased. Accordingly, when the lawn mower  5  is brought into contact with the one height regulation stopper  36 , left and right balance is not lost, and it is possible to perform stable operation. 
         [0048]      FIG. 5  illustrates a plan view of the lawn mower  5  of the work vehicle in the embodiment of the present invention. An inner configuration of the lawn mower  5  is the same as the one illustrated in JP 2012-70696 A. The lawn mower  5  has three reaping blades, and each reaping blade is rotated around a vertical rotational shaft. The power from the PTO shaft  6  is used to rotate each reaping blade through a transmission belt. The reaped lawn is discharged from a discharge port  24   a.  A cover of the lawn mower  5  is fixed to the lawn mower  5  body by four hooks  22 . The four hooks  22  are provided at positions which are not brought into contact with the fuel tanks  16 L,  16 R located above. Specifically, the hooks  22  are provided so as to be positioned on both sides with the fuel tanks  16 L,  16 R therebetween. By providing in this way, the raising and lowering stroke of the lawn mower  5  can be large. 
         [0049]      FIG. 11  illustrates a left side view of a work vehicle according to a second embodiment. A loader can be mounted to a vehicle front of the work vehicle as a work machine. Raising and lowering and a posture of the loader are controlled by hydraulic pressure from the work vehicle. In the work vehicle of the second embodiment, a front manifold for providing the hydraulic pressure to the loader is disposed on a right side surface of the vehicle body. Specifically, the front manifold is constituted of a cover body  20 , and four pipe joints are provided at a front part of the cover body  20 . Pipe joints  21 ,  21  supply operation oil at the time of raising and lowering of the loader, and pipe joints  21 ,  21  supply operation oil when a posture of a bucket of the loader is inclined forward or inclined rearward. Further, the above-described cover body  20  is configured to cover a fuel filter. The fuel filter is normally disposed within an engine room in a hood  11 , or directly mounted to an engine  10 . However, in a case where a DPF is disposed within the engine room, it is necessary to move the fuel filter to a separate place. Therefore, in the present case, the fuel filter is mounted to a front part of a right step SR for getting on/off a cabin  9 , and the fuel filter is covered with the cover. 
         [0050]    At this time, in the same way as the mid link  45 , a piping of a hydraulic hose from a hydraulic pump (not illustrated) located on a rear side of a transmission case  3  to the four pipe joints  21  is arranged between the transmission case  3  and the right fuel tank  16 R so as to pass through above a communication pipe  17 . By arranging in this way, even in a case where the lawn mower  5  is raised to a non-working position, the hydraulic hose is not sandwiched between the lawn mower  5  and the fuel tank  16 R. Further, in a case where height regulation stoppers  36 ,  36  are provided on outer sides of engagement parts  44 ,  44 , interference with these hydraulic hoses can be reduced. 
         [0051]    Other embodiments of the invention will be apparent to those skilled in the art from consideration of the specification and practice of the invention disclosed herein. It is intended that the specification and examples be considered as exemplary only, with a true scope and spirit of the invention being indicated by the following claims.