Patent Publication Number: US-2023159109-A1

Title: Tractor

Description:
BACKGROUND 
     Technical Field 
     The present invention relates to a tractor. 
     Description of Related Art 
     Among tractors, there are those that, as illustrated in patent literature 1 for example, are provided with an engine bonnet (bonnet) forming an engine compartment; a first exhaust-gas cleaning device (first case) that, in the engine compartment, is provided above an engine (diesel engine) and subjects exhaust gas from the engine to a cleaning process; and a second exhaust-gas cleaning device (second case) that is provided behind the engine and subjects the exhaust gas from the engine to a cleaning process. 
     PRIOR-ART LITERATURE 
     
         
         [Patent Literature 1] JP 6188219 B2 
       
    
     In the above tractors, the first exhaust-gas cleaning device is housed above the engine, and the second exhaust-gas cleaning device is housed behind the engine. This increases an up-down length and a front-back length of the engine compartment and increases a volume of the engine compartment such that a large engine bonnet is necessary. 
     SUMMARY 
     One or more embodiments of the present invention provide a tractor wherein it is easy to open and close an engine compartment despite an engine bonnet being large and wherein the engine bonnet is easy to produce. 
     A tractor of one or more embodiments of the present invention is provided with: 
     a vehicle body; an engine bonnet forming an engine compartment; and a first exhaust-gas cleaning device, which is provided above an engine in the engine compartment and subjects exhaust gas from the engine to a cleaning process (purifies the exhaust gas from the engine), and second exhaust-gas cleaning device, which is provided behind the engine and subjects the exhaust gas from the engine to a cleaning process (purifies the exhaust gas from the engine); wherein the engine bonnet has a back bonnet, which covers a back engine compartment portion—wherein the second exhaust-gas cleaning device is positioned—of the engine compartment and a front bonnet, which is configured as a separate body from the back bonnet in a state of covering a front engine compartment portion—disposed further toward a vehicle-body front side than the back engine compartment portion—of the engine compartment; and the front bonnet is supported in a state wherein it can swing open and closed (swingably supported to open and close). 
     According to the present configuration, even if an overall size of the engine bonnet is large, the engine compartment can be opened and closed by performing an operation of swinging only the front bonnet. This facilitates opening and closing the engine compartment. The engine bonnet can be produced by being divided into the front bonnet and the back bonnet. This facilitates production of the engine bonnet. 
     In one or more embodiments of the present invention, 
     the front bonnet is supported in a state of being able to swing open and closed, up and down (vertically swingably supported to open and close), by using as a swinging fulcrum a pivot shaft core extending along a vehicle-body lateral width direction at a back end portion of the front bonnet. 
     According to the present configuration, an operation of raising a front end side of the front bonnet opens the front bonnet, and an operation of lowering the front end side of the front bonnet closes the front bonnet. This facilitates opening and closing the front bonnet. 
     In one or more embodiments of the present invention, 
     the front bonnet has a front top plate portion (i.e., a front top plate) and front side plate portions (i.e., front side plates) that extend downward from left and right side portions (i.e., left and right sides) of the front top plate portion, the back bonnet has a back top plate portion (i.e., a back top plate) that covers the back engine compartment portion from above and left and right back side plate portions (i.e., back side plates) that cover the back engine compartment portion from both horizontal sides, provided is a connecting bolt that connects a front portion of the back side plate portion to a support member (i.e., a supporting tool), and the front bonnet is configured to cover the connecting bolt in a closed state with a back portion of the front side plate portion is positioned on a horizontal outer side of the connecting bolt. 
     According to the present configuration, the front bonnet becomes a cover covering the connecting bolt from the horizontal outer side. As such, a simple cover structure that requires no special cover can prevent, for example, water leakage into the connecting bolt. 
     In one or more embodiments of the present invention, 
     the back bonnet has a back top plate portion (i.e., a back top plate) that covers the back engine compartment portion from above and left and right back side plate portions (i.e., back side plates) that cover the back engine compartment portion from both horizontal sides, and the back top plate portion and the left and right back side plate portions are configured as separate bodies. 
     According to the present configuration, the back bonnet can be produced by being divided into the back top plate portion and the left and right back side plate portions. This facilitates production of the back bonnet. 
     In one or more embodiments of the present invention, 
     the second exhaust-gas cleaning device is configured to use a reducing agent to subject the exhaust gas from the engine to the cleaning process (purify the exhaust gas from the engine using the reducing agent), and a reducing-agent tank and a reducing-agent pump, which supplies the reducing agent stored in the reducing-agent tank to the second exhaust-gas cleaning device, are provided on a front side of the engine in the front engine compartment portion. 
     According to the present configuration, a front-back length of the engine compartment becomes longer due to a space housing the reducing-agent tank and the reducing-agent pump, making an engine bonnet of a longer front-back length necessary. However, the engine bonnet can be produced by being divided into the front bonnet and the back bonnet. This facilitates production of the engine bonnet. 
    
    
     
       BRIEF DESCRIPTION OF DRAWINGS 
         FIG.  1    is a left side view illustrating an entirety of a tractor. 
         FIG.  2    is a plan view illustrating the entirety of the tractor. 
         FIG.  3    is a side view illustrating a motor unit. 
         FIG.  4    is a side view illustrating support structures of a front bonnet and a back bonnet. 
         FIG.  5    is a front view illustrating the support structure of the back bonnet. 
         FIG.  6    is a perspective view illustrating the back bonnet, a bonnet support member, and a partition member in an exploded state. 
     
    
    
     DETAILED DESCRIPTION OF EMBODIMENTS 
     Embodiments the present invention are described below based on the drawings. 
     Note that in the following description, in regards to a traveling vehicle body of a tractor, the direction of arrow F illustrated in  FIGS.  1  and  2    is defined as “vehicle-body front”, the direction of arrow B is defined as “vehicle-body back”, the direction of arrow U illustrated in  FIG.  1    is defined as “vehicle-body up”, the direction of arrow D is defined as “vehicle-body down”, the direction of arrow L illustrated in  FIG.  2    is defined as “vehicle-body left”, and the direction of arrow R is defined as “vehicle-body right”. 
     [Overall Configuration of Tractor] 
     As illustrated in  FIGS.  1  and  2   , the tractor is provided with a traveling vehicle body  3  supported by a pair of left and right front wheels  1 , which can be steered and driven, and a pair of left and right back wheels  2 , which can be driven. A vehicle body frame  4  of the traveling vehicle body  3  is constituted by an engine  5 , a flywheel housing  6  connected to a back portion of the engine  5 , a clutch housing  7  connected to a back portion of the flywheel housing  6 , a transmission case  7   a  connected to a back portion of the clutch housing  7 , and a front frame  8  connected to a lower portion of the engine  5 . A motor unit  9  provided with the engine  5  is formed in a front portion of the traveling vehicle body  3 . A driver&#39;s seat  10  and a driving unit  12 , which is provided with a steering wheel  11  whereby a steering operation of the front wheels  1  is performed, are formed in a back portion of the traveling vehicle body  3 . A linking mechanism  13 , which connects a work apparatus such as a rotary tilling apparatus (not illustrated) in a manner enabling a raising and lowering operation of the work apparatus, and a power takeoff shaft  14 , which takes power from the engine  5  and outputs this to the connected work apparatus, are provided in a back portion of the transmission case  7   a .  20  illustrated in  FIGS.  1  and  2    is a ROPS frame. The ROPS frame  20  is configured to be able to change attitudes between a storage attitude, which is a collapsed state of surrounding the motor unit  9 , and a usage attitude, which is a raised state. 
     [Configuration of Motor Unit] 
     As illustrated in  FIGS.  1  and  3   , the motor unit  9  is provided with an engine compartment  15 . The engine compartment  15  is formed by an engine bonnet  16 , which covers the engine compartment  15  from above, the front, and both horizontal sides; a partition member  17  that forms a partition between the engine compartment  15  and the driving unit  12 ; and the like. 
     As illustrated in  FIGS.  1 ,  2  and  3   , the engine  5 , a radiator  18  that cools the engine  5 , a first exhaust-gas cleaning device (DPF)  21  and second exhaust-gas cleaning device (SCR)  22  that perform cleaning processes of exhaust gas exhausted by the engine  5 , a reducing-agent tank  23 , a reducing-agent pump  24 , and a battery  25  are provided in the engine compartment  15 . 
     [Configuration of Radiator] 
     As illustrated in  FIGS.  1 ,  2 , and  3   , the radiator  18  is provided in front of the engine  5 . A blowing action of a rotary fan  19  positioned between the radiator  18  and the engine  5  introduces cooling air from outside the engine compartment  15  to inside the engine compartment and supplies the cooling air to the radiator  18 . The cooling air is supplied to the radiator  18  in a state of the cooling air passing through the radiator  18  from front to back. In the radiator  18 , engine cooling water is cooled by heat exchange between the supplied cooling air and the engine cooling water. The engine  5  is cooled by the cooled engine cooling water being supplied to the engine  5 . 
     [Configurations of First Exhaust-Gas Cleaning Device and Second Exhaust-Gas Cleaning Device] 
     The engine  5  is a diesel engine. As illustrated in  FIGS.  2  and  3   , the first exhaust-gas cleaning device  21  is provided above the engine  5  in a state wherein a long side of the first exhaust-gas cleaning device is substantially parallel to a vehicle-body lateral width direction (or a vehicle-body horizontal direction). A support member (i.e., the supporting tool)  26  is erected on the flywheel housing  6 . A lower portion of the first exhaust-gas cleaning device  21  is supported by a support arm  26   a  provided to the support member  26 . The first exhaust-gas cleaning device  21  is supported by the flywheel housing  6  of the vehicle body frame  4  via the support member  26 . An exhaust-gas suctioning portion  21   a , which is provided to a part on one end side, in the vehicle-body lateral width direction, of the first exhaust-gas cleaning device  21 , and an exhaust-gas exhausting portion  5   a , which is provided to the engine  5 , are connected. An exhaust-gas discharging portion  21   b  is provided to a part on another end side, in the vehicle-body lateral width direction, of the first exhaust-gas cleaning device  21 . 
     In the first exhaust-gas cleaning device  21 , the exhaust gas exhausted by the engine  5  from the exhaust-gas exhausting portion  5   a  is suctioned by the exhaust-gas suctioning portion  21   a  into the apparatus, and diesel microparticles included in the suctioned exhaust gas are collected by a collection filter (not illustrated). This performs an exhaust-gas cleaning process of decreasing the diesel microparticles. The exhaust gas subjected to the cleaning process is discharged from the exhaust-gas discharging portion  21   b.    
     As illustrated in  FIGS.  2  and  3   , the second exhaust-gas cleaning device  22  is provided behind the engine  5  in a state wherein a long side of the second exhaust-gas cleaning device is substantially parallel to the vehicle-body lateral width direction. A front portion of the second exhaust-gas cleaning device  22  is supported by a strut portion  26   b  provided to the support member  26 . The second exhaust-gas cleaning device  22  is supported by the flywheel housing  6  of the vehicle body frame  4  via the support member  26 . An exhaust-gas introduction portion  22   a , which is provided to a part on one end side, in the vehicle-body lateral width direction, of the second exhaust-gas cleaning device  22 , and the exhaust-gas discharging portion  21   b  of the first exhaust-gas cleaning device  21  are connected by a connecting pipe  27 . An exhaust-gas discharging portion  22   b  is provided to a part on another end side, in the vehicle-body lateral width direction, of the second exhaust-gas cleaning device  22 . 
     In the second exhaust-gas cleaning device  22 , the exhaust gas discharged by the first exhaust-gas cleaning device  21  from the exhaust-gas discharging portion  21   b  is supplied by the connecting pipe  27  to the exhaust-gas introduction portion  22   a  and introduced by the exhaust-gas introduction portion  22   a  into the apparatus, and the introduced exhaust gas is subjected to the cleaning process by a reducing agent. Specifically, aqueous urea as the reducing agent is injected into the introduced exhaust gas, hydrolyzing the exhaust gas. This performs an exhaust-gas cleaning process of decreasing nitrogen oxides included in the exhaust gas. The exhaust gas subjected to the cleaning process is exhausted from the exhaust-gas discharging portion  22   b  to a vehicle-body horizontal outer side. 
     As illustrated in  FIGS.  2  and  3   , the reducing-agent tank  23 , the reducing-agent pump  24 , and the battery  25  are provided on a front side of the engine  5 . In one or more embodiments, the reducing-agent tank  23 , the reducing-agent pump  24 , and the battery  25  are lined up in the vehicle-body lateral width direction. A support plate  28  is provided on an upper side of the front frame  8 . The reducing-agent tank  23  is supported by the support plate  28  via a tank case  23   a . The reducing-agent tank  23  has a pour tube  23   b  that extends forward and upward from an upper portion of the reducing-agent tank  23  and stores the aqueous urea as the reducing agent by the aqueous urea being poured in from the pour tube  23   b . The reducing-agent pump  24  extracts the aqueous urea stored in the reducing-agent tank  23  from the reducing-agent tank  23  and supplies the extracted aqueous urea to the second exhaust-gas cleaning device  22  via a hose (not illustrated) extending from the reducing-agent pump  24  to the second exhaust-gas cleaning device  22 . 
     [Configuration of Engine Bonnet] 
     As illustrated in  FIGS.  1 ,  2 , and  3   , the engine bonnet  16  has a back bonnet  30 , which covers a back engine compartment portion  15 B—wherein the second exhaust-gas cleaning device  22  is positioned—of the engine compartment  15 , and a front bonnet  31 , which covers a front engine compartment portion  15 F—disposed further toward a vehicle-body front side than the back engine compartment portion  15 B—of the engine compartment  15 . The front engine compartment portion  15 F houses the first exhaust-gas cleaning device  21 , the engine  5 , the radiator  18 , the reducing-agent tank  23 , the reducing-agent pump  24 , and the battery  25 . The front bonnet  31  and the back bonnet  30  are configured as separate bodies. 
     [Configuration of Front Bonnet] 
     As illustrated in  FIGS.  1 ,  2 , and  3   , the front bonnet  31  has a front top plate portion  31   a  that covers the front engine compartment portion  15 F from above, a front grille portion  31   b  that extends downward from a front portion of the front top plate portion  31   a  and covers the front engine compartment portion  15 F from the front, and left and right front side plate portions  31   c  that extend downward from both horizontal side portions of the front top plate portion  31   a  and cover the front engine compartment portion  15 F from both horizontal sides. 
     The front bonnet  31  is supported in a state wherein it can be opened and closed. 
     Specifically, as illustrated in  FIGS.  2 ,  3 , and  4   , a bonnet support member  32  extending forward from an upper portion of the partition member  17  is provided in a back portion of the engine compartment  15 . As illustrated in  FIG.  6   , the bonnet support member  32  is configured by combining a plurality of steel members extending in a vehicle-body longitudinal (front-back) direction and a plurality of steel members extending in the vehicle-body lateral width direction. As illustrated in  FIGS.  3  and  6   , a pivot shaft  34  extending in the vehicle-body lateral width direction is provided across a connecting portion  33 , provided to a back end portion of the front bonnet  31 , and a front portion of the bonnet support member  32 . The front bonnet  31  is supported by the bonnet support member  32  in a state of being able to swing between a raised, open state—wherein, as illustrated by the solid lines in  FIG.  4   , the engine compartment  15  is opened by using, as a swinging fulcrum, a pivot shaft core P extending in the vehicle-body lateral width direction of the pivot shaft  34 —and a lowered, closed state—wherein, as illustrated by the dot-dot-dash lines in  FIG.  4   , the engine compartment  15  is closed. 
     As illustrated in  FIG.  3   , a support member  35  extends forward, passing above the engine  5 , from the support member  26  of the first exhaust-gas cleaning device  21  and the second exhaust-gas cleaning device  22 . A support rod  36  that causes the support member  35  to support the bonnet support member  32  is connected across an arm portion  35   a  provided to a front portion of the support member  35  and an arm portion  32   a  provided to the front portion of the bonnet support member  32 . A damper  37  that biases the front bonnet  31  to the open state is connected across the arm portion  35   a  and an inner portion of the front bonnet  31 . 
     [Configuration of Back Bonnet] 
     As illustrated in  FIGS.  1 ,  2 , and  3   , the back bonnet  30  has a back top plate portion  30   a , which covers the back engine compartment portion  15 B from above, and left and right back side plate portions  30   b , which cover the back engine compartment portion  15 B from both horizontal sides. As illustrated in  FIG.  6   , the back top plate portion  30   a  and the left and right back side plate portions  30   b  are configured as separate bodies. The back top plate portion  30   a  and the left and right back side plate portions  30   b  are constituted by sheet-metal members. 
     As illustrated in  FIGS.  4  and  5   , the back bonnet  30  is configured to be supported by the partition member  17 , the bonnet support member  32 , and side-plate support members  38 . 
     Specifically, as illustrated in  FIGS.  4  and  5   , the side-plate support members  38  extend upward from both horizontal side portions of the flywheel housing  6 . Upper end portions of the side-plate support members  38  are connected to a front side portion of the bonnet support member  32 , and the side-plate support members  38  are configured to serve as support members of the bonnet support member  32 . 
     As illustrated in  FIG.  6   , connecting portions  39  are respectively provided to a front portion and a back portion of the back top plate portion  30   a . In one or more embodiments, the front portion and the back portion of the back top plate portion  30   a  are each provided with two connecting portions  39 . As illustrated in  FIGS.  3 ,  4 , and  5   , the back top plate portion  30   a  is supported by the partition member  17  and the bonnet support member  32  by the connecting portions  39  of the back portion being pin-connected to the partition member  17  and the connecting portions  39  of the front portion being pin-connected to a support portion  32   b  provided to the front portion of the bonnet support member  32 . 
     As illustrated in  FIG.  6   , at each of the left and right back side plate portions  30   b , a front connecting portion  40  is provided to a front portion of the back side plate portion  30   b  and a back connecting portion  41  is provided to a back portion of the back side plate portion  30   b . In one or more embodiments, two front connecting portions  40  and two back connecting portions  41  are provided. As illustrated in  FIGS.  4  and  5   , the left and right back side plate portions  30   b  are each supported by the side-plate support member  38  and the partition member  17  by the front connecting portion  40  being connected to the side-plate support member  38  by a connecting bolt  42  and the back connecting portion  41  being pin-connected to the partition member  17 . 
     As illustrated by the solid lines in  FIG.  1    and the dot-dot-dash lines in  FIG.  4   , the front bonnet  31  is configured so in the closed state, a back portion  31   d  of the front side plate portion  31   c  of the front bonnet  31  is positioned on a horizontal outer side of the connecting bolt  42  so as to cover the connecting bolt  42 . The front side plate portion  31   c  of the front bonnet  31  prevents exposure of and water leakage into the connecting bolt  42 . 
     The engine bonnet  16  has the back bonnet  30 , which covers the back engine compartment portion  15 B—wherein the flywheel housing  6  is positioned—of the engine compartment  15 , and the front bonnet  31 , which covers the front engine compartment portion  15 F—disposed further toward the vehicle-body front side than the back engine compartment portion  15 B—of the engine compartment  15 . The front bonnet  31  and the back bonnet  30  are configured as separate bodies. The front bonnet  31  is supported in a state wherein it can swing open and closed. 
     Other Embodiments 
     (1) The above embodiments illustrate an example wherein the front bonnet  31  is supported so as to be able to swing open and closed, up and down, by using as a swinging fulcrum the pivot shaft core P in the vehicle-body lateral width direction provided to the back end portion of the front bonnet  31 . However, the present invention is not limited thereto. For example, the front bonnet may be supported so as to be able to swing open and closed, up and down, by using as a swinging fulcrum a pivot shaft core in the vehicle-body lateral width direction positioned in a front end portion of the front bonnet  31 . Alternatively, the front bonnet may be supported so as to be able to swing open and closed by using as a swinging fulcrum a pivot shaft core positioned in a state of extending in the vehicle-body longitudinal direction to a horizontal side portion of the front bonnet  31 . 
     (2) The above embodiments illustrate an example wherein the back top plate portion  30   a  and the left and right back side plate portions  30   b  are configured as separate bodies. However, these may be integrally configured. 
     (3) The above embodiments illustrate an example of adopting a configuration wherein the connecting bolt  42  is covered from the horizontal side by the back portion  31   d  of the front bonnet  31  in the closed state. However, this configuration does not need to be adopted. 
     (4) The above embodiments illustrate an example wherein the reducing-agent tank  23  and the reducing-agent pump  24  are provided on the front side of the engine  5  in the front engine compartment portion  15 F, but the present invention is not limited thereto. 
     For example, the reducing-agent tank  23  and the reducing-agent pump  24  may be provided in any location, such as outside the engine compartment  15 . 
     INDUSTRIAL APPLICABILITY 
     The one or more embodiments of present invention can be applied in tractors provided with an engine bonnet forming an engine compartment, a first exhaust-gas cleaning device provided above an engine in the engine compartment, and a second exhaust-gas cleaning device provided behind the engine. 
     Although the disclosure has been described with respect to only a limited number of embodiments, those skilled in the art, having benefit of this disclosure, will appreciate that various other embodiments may be devised without departing from the scope of the present invention. Accordingly, the scope of the invention should be limited only by the attached claims.