Abstract:
A tractor includes a plurality of wheels; a vehicle body frame supported by the wheels; an engine supported by the vehicle body frame; an engine hood for covering the engine; a cabin disposed rearwardly of the engine hood; an engine hood support frame for supporting the engine hood; wherein a gap is formed between the engine hood and the cabin and a gap is formed between the engine hood support frame and the cabin; an engine side sound insulating wall closing a rearward opening of the engine hood; a cabin side sound insulating wall provided to the cabin in opposition to the engine side sound insulating wall wherein the engine side sound insulating wall and the cabin side sound insulating wall defining a gap therebetween which opens to exterior space outside the cabin.

Description:
BACKGROUND OF THE INVENTION 
       [0001]    The present invention relates to a tractor having a cabin rearwardly of an engine hood of an engine section relative to a vehicle body. 
         [0002]    A tractor of this type is known from e.g. JP2001-122165. This tractor includes an engine hood, a cabin, an extension portion provided in a rear end plate and a partition wall plate bolt-connected to this extension portion. The extension portion of the rear end plate and the partition wall plate partition an engine room from a driving section, so as to restrict transmission of noise to the driving section. The extension portion of the rear end plate extends to a position upwardly of the engine room so as to partition the engine room from the driving section, thus providing sound insulation for the driving section. 
         [0003]    When the above-described prior art is adopted, in order to obtain good sound insulation for the cabin, it is necessary to provide good precision in the partitioning between the inside of the engine hood and the cabin and restriction of the noise transmission. If this was to be done, this would impose difficulty in the manufacture of the partition wall, the cabin, etc. so that the partition wall, the cabin, etc. may obtain good sealing performance and sound insulating performance. 
       SUMMARY OF THE INVENTION 
       [0004]    The object of the present invention is to provide a tractor having good sound insulating performance for its driving section and being advantageous in its manufacture. 
         [0005]    A tractor, according to the present invention, comprises: 
         [0006]    a plurality of wheels; 
         [0007]    a vehicle body frame supported by the wheels; 
         [0008]    an engine supported by the vehicle body frame; 
         [0009]    an engine hood for covering the engine; 
         [0010]    a cabin disposed rearwardly of the engine hood; 
         [0011]    an engine hood support frame for supporting the engine hood wherein a gap is formed between the engine hood and the cabin and a gap is formed between the engine hood support frame and the cabin; 
         [0012]    an engine side sound insulating wall closing a rearward opening of the engine hood; 
         [0013]    a cabin side sound insulating wall provided to the cabin in opposition to the engine side sound insulating wall wherein the engine side sound insulating wall and the cabin side sound insulating wall defining a gap therebetween which opens to exterior space outside the cabin. 
     
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0014]      FIG. 1  is a general side view of a tractor, 
           [0015]      FIG. 2  is a side view in vertical section showing a rear portion of an engine section and a front portion of a cabin, 
           [0016]      FIG. 3  is a plan view in section showing the rear portion of the engine section and the front portion of the cabin, 
           [0017]      FIG. 4  is a rear view showing a sound insulating plate disposing portion of the engine section, and 
           [0018]      FIG. 5  is a perspective view showing a rear engine hood support frame and a sound insulting plate. 
       
    
    
     DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS 
       [0019]    Embodiments of the invention will be described next with reference to the accompanying drawings. 
         [0020]      FIG. 1  is a general side view of a tractor relating to an embodiment of the present invention. As shown, the tractor relating to the embodiment of the invention includes a self-propelling vehicle body having a pair of right and left steerable and drivable front wheels  1 ,  1  and a pair of right and left drivable rear wheels  2 ,  2 , an engine section  10  having an engine hood  11  provided at a front portion of a vehicle body frame  3  of this self-propelling vehicle body, a driving section having a cabin  20  provided rearwardly of the engine hood  11  relative to the vehicle body, lift arms  5  provided on opposed lateral sides of an upper portion of a transmission case  4  constituting a rear portion of the vehicle body frame  3 , and a power takeoff (PTO) shaft  6  provided at a rear portion of the transmission case  4 . 
         [0021]    To the rear portion of the vehicle body of this tractor, various work implements can be operably connected to be liftable and drivable, thus rendering the tractor into various work vehicles. For instance, a rotary plow implement can be connected to be lifted up/down to the rear portion of the vehicle body via a link mechanism utilizing the pair of right and left lift arms  5 ,  5  and power can be transmitted to this rotary plow implement via the PTO shaft  6 . In this case, the tractor is provided as a riding type plowing machine. 
         [0022]    The vehicle body frame  3  includes an engine  12 , a transmission case  7  connected to a rear portion of the engine  12 , the transmission case  4  connected to a rear portion of the transmission case  7 , and a front wheel frame  8  extending forwardly relative to the vehicle body from under the engine  12 . 
         [0023]    The engine section  10  includes the engine hood  11  and includes also the engine  12  disposed inside this engine hood  11 , and an engine fuel tank  13  disposed rearwardly and upwardly of the engine  12 . The engine hood  11  includes a pair of right and left lower hoods  11   a ,  11   a , a single front hood  11   b , and a single upper hood  11   c . The right and left lower hoods  11   a ,  11   a  are detachably supported to a rear engine hood support frame  14  (see  FIGS. 2 and 5 ) having a lower end thereof connected to the transmission case  7  and also to a front support frame  15  (see  FIG. 1 ) provided at a front portion of the front wheel frame  8 . As shown in  FIG. 2 , a rear end side upper portion of the upper hood  11   c  is pivotally connected to a support portion  16  located at an upper end portion of the rear engine hood support frame  14 , so that the upper hood  14   c  is vertically pivoted about an a lateral axis included in the support portion  16  to be opened/closed. As shown in  FIG. 5 , the rear engine hood support frame  14  includes a pair of right and left vertical frame portions  14   a  oriented vertical relative to the vehicle body and having lower ends thereof connected to the transmission case  7  and a lateral frame portion  14   b  oriented lateral relative to the vehicle body and interconnecting respective upper ends of the right and left vertical frame portions  14   a , so that the rear engine support frame  14  as a whole presents a portal shape as viewed along the fore and aft direction of the vehicle body. 
         [0024]    The cabin  20  includes a front wall  21 , a pair of right and left lateral walls  22 ,  22 , a rear wall  23  and a top plate  24 . The front wall  21  includes a driver&#39;s panel  25  provided on the inner face side of the front wall  21  and at a center of the lower portion of the front wall  21  relative to the right/left direction. The front wall  21  and the rear wall  23  include transparent plates constituting most parts of the front wall  21  and the rear wall  23 . The right and left lateral wall  22  include an entrance/exit door  26  and a curved lower edge portion  27 . The curved lower edge portion  27  has a curved shape extending along a rear wheel fender  9  so that the lateral wall  22  may be disposed upwardly of the rear wheel fender  9 . The entrance/exit door  26  is opened/closed as being pivoted about a vehicle-body-wise vertical axis located at a rear end of this entrance/exit door  26 . 
         [0025]    As shown in  FIG. 1 , the cabin  20  is connected to the vehicle body  3  via a pair of front connecting portions  28  disposed so as to be located on opposed lateral outer sides of the transmission case  7  and a pair of rear connecting portions  29  disposed so as to be located on the opposed lateral sides of the rear portion of the transmission case  4 . The pair of right and left front connecting portions  28  and the pair of right and left rear connecting portions  29  include damper rubbers  30  interposed between vehicle side cabin attaching members included in the transmission case  7  and the transmission case  4  and cabin side connecting members included in the cabin, so that the cabin  20  is connected to the vehicle body frame  3  with transmission of vibration from the vehicle body frame  3  to the cabin  20  being lessened. 
         [0026]      FIG. 2  is a side view in vertical section showing a front portion of the cabin  20  and a rear portion of the engine section  10 .  FIG. 3  is a plan view in section showing the front portion of the cabin  20  and the rear portion of the engine section  10 . As shown in these drawings, a gap  40  is provided between the engine section  10  and the cabin  20 . At a rear portion of the engine section  10 , there is provided an engine section side sound insulating wall  41 . The front wall  21  of the cabin  20  includes a cabin side sound insulating wall  42  provided in opposition to the engine section side sound insulating wall  41 . A gap  43  is provided between the engine section side sound insulating wall  41  and the cabin side sound insulating wall  42 . The arrangements provide sound proof for the cabin  20  so as to restrict noise transmission from the engine section  10  to the cabin  20 . 
         [0027]    More particularly, the gap  40  is a gap provided among the engine hood  11 , the rear engine hood support frame  14  and the cabin  20 . This gap  40  restricts transmission of vibration from the engine hood  11  to the cabin  20  and also restricts transmission of vibration from the rear engine hood support frame  14  to the engine  20 . 
         [0028]    The engine section side sound insulating wall  41  of the engine section  10  is comprised of an iron plate connected via connecting screws  45  to a pair of upper and lower stays  44 ,  44  (see  FIGS. 2 and 5 ) included in a pair of right and left vertical frame portions  14   a  of the rear engine hood support frame  14 . For forming this engine section side sound insulating wall  41 , aside from iron, any other metal or resin can also be used. 
         [0029]    As shown in  FIGS. 4 and 5 , the engine section side sound insulating wall  41  includes a sealing member  46  attached to a peripheral edge of the engine section side sound insulating wall  41 , so that this sealing member  46  seals between the engine section side sound insulating wall  41 , the upper hood  11   e  and the lower hood  11   a . That is, the engine section side sound insulating wall  41  closes a rearward opening  11   d  of the engine hood  11  so as to restrict noise transmission from the rearward opening  11   d  of the engine hood  11  to the outside. The engine section side sound insulating wall  41  includes a bulging portion  41   a  formed to project rearward relative to the vehicle body at a center of this engine section side sound insulating wall  41  relative to the vehicle body. This bulging portion  41   a  serves to avoid interference between the engine section side sound insulating wall  41  and a portion  13   a  of the fuel tank  13  projecting rearward relative to the vehicle body from the rear engine hood support frame  14 . As shown in  FIGS. 4 and 5 , the engine section side sound insulating wall  41  includes an extension plate  41   b  extending downward relative to the vehicle body from the lower end of the engine side sound insulating wall  41 . The extension plate  41   b  covers the space between the lower hoods  11   a  and the transmission case  7 . 
         [0030]    A gap  43  between the engine side sound insulating wall  41  and the cabin side sound insulating wall  42  is provided over the entire surface of the engine side sound insulating wall  41 . This gap  43  is open to the outside of the cabin  20  over the entire perimeter of the engine hood  11 . Namely, the gap  43  is intended to damp and relieve noise which may be transmitted from the engine section side sound insulating wall  41  to the cabin  20 . 
         [0031]    The cabin side sound insulating wall  42  of the cabin  20  includes an iron plate  47  as a first plate connected to a frame member  21   a  of the front wall  21 , a rubber plate  48  as a second plate provided on the outer side of this iron plate  47 , i.e. on the side facing the engine section side sound insulating wall  41 , and a gap  49  provided between the rubber plate  48  and the iron plate  47 . The gap  49  is formed by a spacer  50  attached by a connecting pin affixing the rubber plate  48  to the iron plate  47  and is formed over the entire surface of the rubber plate  48 . Namely, the cabin side sound insulating wall  42  restricts noise transmission to the cabin  20  through damping or relief of transmission of noise by the iron plate  47 , the rubber plate  48  and the gap  49 . 
         [0032]    The first plate can be formed of any other metal than iron or even resin. The rubber plate  48  as the second plate too can be formed of an iron plate, any other metal or resin.