Abstract:
An air conditioning arrangement for a work vehicle having a cabin includes: a hood disposed forwardly of the cabin; an air conditioning unit housed in the hood forwardly of the cabin; and a dashboard provided in a front portion in the cabin. The air conditioning unit includes a rear duct for delivering conditioned air rearward and a front duct having a portion for delivering conditioned air frontward. The front duct further has a portion extending rearward under the air conditioning unit. The dashboard includes an upper outlet, a defrost outlet and a lower outlet. Each of the upper outlet, the defrost outlet and the lower outlet is communicated with either one of the front duct and the rear duct.

Description:
BACKGROUND OF THE INVENTION 
       [0001]    The present invention relates to a structure of an operating unit of a work vehicle that can be used for various purposes including freight transportation use, leisure use and light duty use, etc. 
         [0002]    The work vehicle is known to include an operating unit covered by a roof, serving as a sunshade, attached to an overturn protection frame as disclosed in JP2005-178783A. 
         [0003]    Work vehicles of this type are desired to include a cabin serving as an operating unit. In this case, air conditioning is necessary in the cabin. 
       SUMMARY OF THE INVENTION 
       [0004]    The present invention has been made to satisfy this demand. It is an object of the present invention to provide a structure of an operating unit of a work vehicle having a comfortably air conditioned cabin that ensures excellent forward visibility, which allows the operator to work in a comfortable environment. 
         [0005]    The air conditioning arrangement for a work vehicle having a cabin of the present invention is an air conditioning arrangement comprising: a hood disposed forwardly of the cabin; an air conditioning unit housed in the hood forwardly of the cabin; and a dashboard provided in a front portion in the cabin, the air conditioning unit comprising a rear duct for delivering conditioned air rearward and a front duct comprising a portion for delivering conditioned air frontward, the front duct further comprising a portion extending rearward under the air conditioning unit, the dashboard comprising an upper outlet, a defrost outlet and a lower outlet, wherein each of the upper outlet, the defrost outlet and the lower outlet is communicated with either one of the front duct and the rear duct. 
         [0006]    As described above, by delivering the conditioned air discharged from the air conditioning unit separately to the front duct and to the rear duct, it is possible to supply the conditioned air separately to the upper outlet and the lower outlet through different paths. By controlling the paths and the outlets to open or close, it is possible to provide conditioned air suitable according to cooling operation or heating operation. 
         [0007]    Because the front duct is extended rearward under the air conditioning unit, it is possible to reduce the occupancy of the air conditioning equipment in the hood, and therefore a reduction in height of the hood can be achieved. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0008]      FIG. 1  is an overall side view of a work vehicle. 
           [0009]      FIG. 2  is an overall plan view of the work vehicle. 
           [0010]      FIG. 3  is a plan view illustrating an arrangement of an air conditioner. 
           [0011]      FIG. 4  is a vertical cross-sectional side view of the air conditioner. 
           [0012]      FIG. 5  is a front view of a dashboard. 
           [0013]      FIG. 6  is a front view of an air conditioner control unit. 
           [0014]      FIG. 7  is a plan view illustrating air flow in cooling operation mode. 
           [0015]      FIG. 8  is a plan view illustrating air flow in cooling/defrost operation mode. 
           [0016]      FIG. 9  is a plan view illustrating air flow in heating operation mode. 
       
    
    
     DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS 
       [0017]    A preferred embodiment of the present invention will be described below with reference to the accompanying drawings. 
         [0018]      FIG. 1  shows a side view of a multi-purpose vehicle as an example of a work vehicle.  FIG. 2  shows a plan view of the multi-purpose vehicle. This work vehicle basically includes: a body frame  1  with a stepped shape in which a front portion is lower than a rear portion; laterally steerable front wheels  2  independently suspended from the front portion of the body frame  1 ; laterally steerable rear wheels  3  independently suspended from the rear portion of the same; a power unit  4  located under the rear portion of the body frame  1 ; a cabin  5  serving as an operating unit located in the middle of the front-rear direction of the body frame  1 ; a hood  6  connected to a front end of the cabin  5  and mounted on the front portion of the body frame  1 ; and a load unit  8  located above the rear portion of the body frame  1  and capable of pivoting around a fulcrum p by a hydraulic cylinder  7 . 
         [0019]    The power unit  4  includes a mounting frame  9  located under the rear portion of the body frame  1  and supported in a vibration-isolating manner, an engine  10  and a transmission case  11  connected directly to the engine  10  located in front thereof, the engine  10  and the transmission case  11  being mounted on the mounting frame  9 . While the power varied in speed in the transmission case  11  is transmitted to the right and left rear wheels  3 , the right and left front wheels  2  are driven by the running power axially transmitted from the transmission case  11  to the front portion of the body, whereby four wheel drive is performed. 
         [0020]    In the cabin  5 , a double seat  12  with an operator seat on the left and a passenger seat on the right is provided in the back, and a dashboard  13  is provided in the front. As shown in  FIG. 5 , driving controls and instruments including a steering wheel  14 , a gear shift lever  15 , etc. are provided on the left side of the dashboard  13 . Although not shown, under the left side of the dashboard  13 , an accelerator pedal and a brake pedal are provided on the floor. 
         [0021]    The hood  6 , which is capable of being opened and closed, includes air conditioning equipment such as an air conditioning unit  20 , an air conditioning condenser  21 , etc. as shown in  FIG. 3 . As shown in  FIG. 7 , the air conditioning unit  20  includes an evaporator  22  to which a refrigerant condensed in the condenser  21  is delivered, a heater  23  and a vertical type blowing fan  24  for blowing out conditioned air. The condenser  21  is cooled by an electric fan  25 . 
         [0022]    As shown in  FIG. 5 , a pair of right and left center grille outlets  26  serving as upper outlets U are provided at the upper center between the right and left sides of the dashboard  13 . Side grille outlets  27  serving as another upper outlets U are provided near the right and left sides of the dashboard  13 , respectively. A pair of right and left defrost grille outlets  28  are provided on the top of the dashboard  13 . Under the dashboard  13 , foot grille outlets  29  serving as lower outlets D are provided on the right and left sides, respectively. 
         [0023]    The center grille outlets  26  and the side grille outlets  27  serving as the upper outlets U are capable of changing the flow direction of conditioned air, so that the operator on the left side and the passenger on the right side separately can control the flow direction according to their preferences. The defrost grille outlets  28  discharge conditioned air toward a windshield  5   a  to spread the conditioned air over the windshield  5   a . The foot grille outlets  29  serving as the lower outlets D discharge conditioned air toward the feet of the operator and passenger. 
         [0024]    As shown in  FIG. 4 , the center grille outlets  26  and the side grille outlets  27  are connected to a first internal duct  31  provided in the cabin, whereas the defrost grille outlets  28  and the foot grille outlets  29  are connected to a second internal duct  32  provided also in the cabin. Thereby, the air discharge path of the center grille outlets  26  and the side grille outlets  27  and that of the defrost grille outlets  28  and the foot grille outlets  29  are separated. 
         [0025]    The air conditioning unit  20  includes an intake duct  33  connected to the blowing fan  24  and a main duct  34  for guiding the air blown from the blowing fan  24  to flow in the right direction of the body. An evaporator  22  is disposed in the upstream of the main duct  34 , and a heater  23  is disposed in the downstream of the same. The main duct  34  is connected to a rear duct  35  that discharges conditioned air rearward and to a front duct  36  that discharges conditioned air frontward. The main duct  34  has a temperature control door  37  for controlling the amount of conditioned air discharged to the rear duct  35  and to the front duct  36 , and an air discharge mode switching door  38 . On the right side of the main duct  34 , a bypass  39  that connects the downstream of the heater  23  and the rear duct  35  is provided. 
         [0026]    On the lower left side of the dashboard  13 , the intake duct  33  is communicated with an inside air inlet  40  having a filter attached thereto provided on the front wall  5   b  of the cabin. On the top surface of the intake duct  33 , an outside air inlet  41  having a filter attached thereto is formed. The intake duct  33  has an intake air switching door  42  therein. By moving this intake air switching door  42 , either the inside air of the cabin or the outside air in the hood is selected and introduced into the blowing fan  24 . 
         [0027]    In air conditioning operation mode, a constant amount of refrigerant flows constantly in the evaporator  22 . Upon stopping the air conditioning operation mode, the flow of the refrigerant stops. The heater  23  circulates cooling water (hot water) flowing from a radiator  16  for cooling the engine provided in the power unit  4 . The amount of hot water flowing into the heater  23  can be changed by adjusting the opening of a valve (not shown). 
         [0028]    The rear duct  35  is communicated with the main duct  34  at a position between the evaporator  22  and the heater  23 . The rear end of the rear duct  35  is communicated with the first internal duct  31  in the front wall  5   b  of the cabin. The front duct  36  is communicated with the main duct  34  in the downstream of the heater  23 , and extends rearward under the main duct  34  to the front wall  5   b , where the front duct  36  is communicated with the second internal duct  32 . 
         [0029]    As shown in  FIGS. 5 and 6 , on the right side of the dashboard  13 , there are provided an air conditioning on/off switch  45 , an inside/outside air shift switch  46  for causing the intake air switching door  42  to move, a temperature control dial  47 , an air discharge mode selection dial  48  for selecting the position from which the conditioned air flows into the cabin, and an air flow control dial  49  for adjusting the amount of air flowing from the blowing fan  24  at five different settings (including off). 
         [0030]    The air discharge mode selection dial  48  has three different positions (A), (B) and (C). When the position (A) is selected, the air discharge mode switching door  38  moves to the front closed position (a) as shown in  FIG. 7 . When the position (B) is selected, the air discharge mode switching door  38  moves to the middle position (b) as shown in  FIG. 8 . When the position (C) is selected, the air discharge mode switching door  38  moves to the rear closed position (c) as shown in  FIG. 9 . Examples of the operation will be described below. 
         [0031]    In cooling operation, when the on/off switch  45  is turned on, the temperature control dial  47  is rotated to the cooling mode range on the left side, a desired amount of air flow is selected by the air flow control dial  49 , and the air discharge mode selection dial  48  is set to the position (A), the air discharge mode switching door  38  moves to the front closed position (a), and the temperature control door  37  moves to a position corresponding to the set position of the temperature control dial  47  as shown in  FIG. 7 . 
         [0032]    When the temperature control dial  47  is set to a middle position of the cooling mode range, the temperature control door  37  moves to a middle of its operative range. Thereby, most of the cooled air discharged from the evaporator  22  is delivered to the rear duct  35 , and part of the cooled air discharged from the evaporator  22  is delivered through the heater  23  and the bypass  39  to the rear duct  35 , where the cooled air not having passed through the heater is mixed with the heated air. The mixed air is then delivered to the center grille outlets  26  and the side grille outlets  27  from which the mixed air is discharged. 
         [0033]    In this case, as the temperature control dial  47  is rotated toward the left in order to decrease the cooling temperature, the temperature control door  37  moves toward the open position (i.e., toward the heater), whereby the amount of air passing through the heater  23  is reduced. At the same time, the amount of hot water circulating into the heater  23  is reduced, reducing the amount of heated air to be mixed with the cooling air, and decreasing the temperature of the heated air flowing through the bypass  39 . Thereby, cooled air adjusted to a temperature corresponding to the set position of the temperature control dial  47  is discharged from the center grille outlets  26  and the side grille outlets  27 . When the temperature control dial  47  is rotated to the leftmost position in order to set to the maximum cooling temperature, the temperature control door  37  moves to a position where the temperature control door  37  and the front surface of the heater  23  are aligned, and the circulation of the hot water into the heater  23  is interrupted, and the cooled air having the lowest temperature is delivered to the rear duct  35 . 
         [0034]    During the cooling operation state, when the windshield  5   a  fogs up, by rotating the air discharge mode selection dial  48  to the position (B), the air discharge mode switching door  38  moves to the middle position (b) as shown in  FIG. 8 . Thereby, part of the heated air having passed through the heater  23  is delivered to the front duct  36 , and then discharged from the defrost grille outlets  28  to remove the fog of the windshield  5   a.    
         [0035]    In heating operation, when the on/off switch  45  is turned on, the temperature control dial  47  is rotated to the heating mode range on the right side, a desired amount of air flow is selected by the air flow control dial  49 , and the air discharge mode selection dial  48  is set to the position (C), the air discharge mode switching door  38  moves to the rear closed position (c), and the temperature control door  37  also moves to the closed position as shown in  FIG. 9 . At the same time, the circulation of the refrigerant into the evaporator  22  is interrupted. Accordingly, the air having passed through the evaporator  22  without being controlled in temperature is delivered through the heater  23  to the front duct  36 , and finally discharged from the defrost grille outlets  28  and the foot grille outlets  29 . In this case, as the temperature control dial  47  is rotated toward the right, the amount of hot water circulating into the heater  23  is increased, increasing the temperature of the heated air.