Abstract:
A vehicle including a main body frame having a length direction and a width direction includes a front frame carried by the main body frame. The front frame includes a first front cross frame having a generally height and extends along said main body&#39;s width direction. A second front cross frame is disposed frontward and offset from the first cross frame at an elevational height less than the first front cross frame. A first and second side frame interconnect with the first cross frame and the second cross frame to define radiator cage having an interior space. A radiator is disposed within the interior space of said radiator cage.

Description:
BACKGROUND OF THE INVENTION 
       [0001]    1. Field of the Invention 
         [0002]    The present invention relates to an all terrain vehicle including a radiator mounted frontward of a vehicle body frame in a protective environment. 
         [0003]    2. Description of the Related Art 
         [0004]    In vehicles of the type including a radiator used to maintain the temperature of the engine coolant within a predetermined range, generally the radiator is mounted frontward of the vehicle body frame to increase cooling performance by flowing air. For example, in Japanese Unexamined Patent Application Publication No. 2006-103369, there is proposed a configuration including a radiator mounted frontward of cross pipes. More specifically, a front frame provided frontward of a vehicle body frame is configured into a U-shape in the plan view. The front frame includes left and right extending portions extending along a vehicle in a front-back direction, and cross portions that extend along the vehicle width direction which interconnect with rear ends of the respective left and right extending portions. Additional cross pipes are provided for interconnecting the left and right extending portions in the vehicle width direction. The radiator is mounted frontward of the cross pipes. 
         [0005]    However, in the configuration as in the above-described conventional vehicle in which the radiator is disposed frontward of the cross pipes, while the radiator can be protected against external forces exerted from the vehicle lateral sides, there is a problem in that the radiator cannot be sufficiently protected against external forces exerted from the vehicle front side. 
       SUMMARY OF THE INVENTION 
       [0006]    In view of the foregoing problem, an object of the present invention is to provide a vehicle that enables improving protection for a radiator against external forces exerted from both the vehicle lateral sides and vehicle front side. 
         [0007]    According to one aspect of the present invention, an all terrain vehicle (ATV  1 ) includes a pair of left and right front wheels, a front panel provided rearward of the front wheels, a first front cross frame that is disposed in front of the front panel and extends generally across the vehicle in the width direction, a second front cross frame disposed forward and offset from the first front cross frame and also extending generally along the vehicle&#39;s width direction; a front left side frame and a front right side frame that respectively, are disposed on the left and right sides of the vehicle extending along the vehicle&#39;s front-back direction, and that respectively interconnect the first front cross frame and the second front cross frame. A first bracket is provided near a connection portion of the second front cross frame with the front left side frame, and supports a first cushion unit of a front wheel suspension system. A second bracket is provided near a connection portion of the second front cross frame with the front right side frame that supports a second cushion unit of a front wheel suspension system. These structures define a radiator cage having an interior. A radiator is mounted in a manner that is located in a rectangular space surrounded by the first front and second front cross frames and the left and right side frames. 
         [0008]    According to the vehicle of the present invention, frame members include outer surfaces which define boundaries which the radiator does not pass. Hence, the first and the second front cross frames and the front left and right side frames function as protection members, thereby improving the protection performance against external forces exerted from both the vehicle lateral sides and vehicle frontward side. 
         [0009]    Further, the first and the second brackets, respectively, for supporting the cushion units are provided near the connection portions of the second front cross frame with the front left and right side frames. Hence, external forces transmitted from the front wheels via the cushion units can be supported by the second front cross frame that has high stiffness, consequently it is possible to increase the support stiffness of the cushion units. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0010]      FIG. 1  is a side view of an all-terrain vehicle of one embodiment of the present invention; 
           [0011]      FIG. 2  is a side view of a vehicle body frame of the vehicle to which a radiator is mounted; 
           [0012]      FIG. 3  is a plan view of the vehicle body frame; 
           [0013]      FIG. 4  is a side view of a front frame of the vehicle body frame; 
           [0014]      FIG. 5  is a front view of the front frame; 
           [0015]      FIG. 6  is a front view of an upper portion of the radiator; and 
           [0016]      FIG. 7  is a side view of a lower portion of the radiator. 
       
    
    
     DESCRIPTION OF THE PREFERRED EMBODIMENTS 
       [0017]    One embodiment of the present invention will be described with reference to the accompanying drawings. 
         [0018]      FIGS. 1 to 7  are views of an all-terrain vehicle of one embodiment of the present invention. In the present embodiment, the front, rear, left, and right refer to the front, rear, left, and right in the state as viewed from a passenger who is sitting in a seat looking toward the front wheels unless otherwise specifically mentioned. Also, as shown in the Figures like parts are identified with the same numeral. The front wheels are the same on both the left and right sides, so they are referenced by like numeral  3 . In some instances only the left side of the vehicle is shown, but it is understood that similar items on the right side, while not shown, are of similar nature. 
         [0019]    With reference to the drawings, all terrain vehicle  1  (ATV  1 ) includes a vehicle body frame  2 , a radiator  19 , an engine unit  3 , a pair of front wheels  4 , and a pair of rear wheels  5 . The radiator  19  is mounted in a front portion of the vehicle body frame  2 . The engine unit  3  is mounted in a central portion of the vehicle body frame  2 . The front wheels  4  are, respectively, disposed in left and right front end portions of the vehicle body frame  2 . The rear wheels  5  are, respectively, disposed in left and right rear end portions. 
         [0020]    The ATV  1  further includes a first seat  6  disposed in a front portion of the vehicle body frame  2 , a second seat  7  disposed rearward of the first seat  6 , a first floor  8  disposed frontward of the first seat  6 , and a second floor  9  disposed between the first and the second seats  6  and  7 . 
         [0021]    The engine unit  3  is disposed between the first and the second floors  8  and  9 . A cargo support  10  is disposed on the rear side of the second seat  7  of the vehicle body frame  2  substantially at the same height as a seat surface of the second seat  7 . 
         [0022]    The vehicle body frame  2  preferably includes main body frame  2   a , pillar frames  2   b , and front frame  2   c.  The left and right front wheels  4  and the engine unit  3  are disposed in the main body frame  2   a.  The pillar frames  2   b  are respectively elevationally formed on the left and right sides of the main body frame  2   a , thereby forming a passenger compartment A. The front frame  2   c  is disposed frontward of passenger compartment A of the main body frame  2   a.  The first and second seats  6  and  7  are disposed inside of the passenger compartment A. 
         [0023]    Main body frame  2   a  includes left and right center members  12  extending along the vehicle in a front-back direction, and front and rear cross members  14 F,  14 R that interconnect between left and right center members  12 . Plate-like cross members  13 interconnect midway portions of the respective center members  12 . Engine unit  3  is mounted to cross members  13 . 
         [0024]    As shown in  FIGS. 1 and 3 , pillar frame  2   b  is connected to outer end portions  14   a  of the front and rear cross members  14 , and includes left and right pillar members  15  and multiple roof members  16 . The left and right pillar members  15  have front and rear passenger entries  15   a  and  15   b  formed therein, and the roof members  16  interconnect between upper end portions of the left and right pillar members  15 L and  15 R. 
         [0025]    The first seat  6  is separated into left and right seats  6 L and  6 R at a predetermined distance along the vehicle width direction. The left and right seats  6  include seat cushions  6   c , seat backs  6   d,  and headrests  6   e.  A steering wheel  17  is disposed frontward of the left seat  6 . The second seat  7  is disposed approximately at the same height as the first seat  6 , and includes a bench seat cushion  7   a  and a seat back  7   b  allowing two persons to be seated. A headrest  7   c  is disposed above the seat back  7   b.    
         [0026]    The ATV  1  further includes a partition wall  23  and a hood  25 . The partition wall  23  partitions the passenger compartment A from a front compartment B. The hood  25  is disposed frontward of the partition wall  23  and opens or closes an upper end portion of the front compartment B. 
         [0027]    As shown in  FIG. 4 , partition wall  23  includes an upper portion  23   a,  a frontwardly declined portion  23   b,  and a lower portion  23   c.  The upper portion  23   a  is disposed in a front end portion of pillar frame  2   b , and instruments (not shown), such as a speed meter, are disposed on it. The frontwardly declined portion  23   b  extends obliquely downward and forward from the upper portion  23   a.  The lower portion  23   c  extends obliquely downward and rearward from the frontwardly declined portion  23   b.  An accelerator pedal (not shown) and a brake pedal are disposed in the lower portion  23   c,  and a front edge portion of the first floor  8  is connected to the lower portion  23   c.    
         [0028]    A tunnel portion  24  extending rearward in continuation with the partition wall  23  is formed in a central portion of the partition wall  23  in the vehicle width direction. The tunnel portion  24  is formed convexly into an upwardly protruding shape, in which an upper end of the tunnel portion  24  is located at substantially the same height as the seat surface of the first seat  6 . 
         [0029]    The front compartment B is a space located ahead of the partition wall  23  and below the hood  25 , and communicates with a space in the tunnel portion  24 . The engine unit  3  is disposed in the tunnel portion  24  located rearward of the partition wall  23 . 
         [0030]    The engine unit  3  includes a water-cooled four-cycle engine  20  mounted in a central portion of the left and right center members  12 ,  12  in the front-back direction, a V-belt type continuously variable transmission  21  that changes and the rotation of the engine  20  and outputs it, and a cooling unit  28  that cools the continuously variable transmission  21 . The engine  20  has a structure formed by overlay-coupling a cylinder body  20   g  and a cylinder head  20   c  on a crankcase  20   f.  More specifically, the engine  20  is mounted in a manner that a crankshaft  20   a  is oriented substantially horizontally along the vehicle width direction, and a cylinder axis line  20   b  is oriented rearward and obliquely upward direction. The engine  20  is disposed so as to be located between the left and right seats  6   a  and  6   b  of the first seat  6 . As viewed from a vehicle lateral side, the engine  20  is disposed such that a portion of the engine  20  overlaps with the first seat  6 . More specifically, the engine  20  is disposed such that the cylinder head  20   c  of the engine  20  overlaps with the seat cushions  6   c.    
         [0031]    An intake pipe  30  extending forward the vehicle front direction from the front sidewall of the cylinder head  20   c  is connected to the front sidewall, and an exhaust pipe  31  extending toward the vehicle rearward direction from a rear sidewall of the cylinder head  20   c  is connected to the rear sidewall. In a top view, the intake pipe  30  and the exhaust pipe  31  are disposed substantially linearly on a substantially vehicle center line along the front-back direction. 
         [0032]    The exhaust pipe  31  includes a first vertical tube portion  31   b,  a transverse tube portion  31   c,  a second longitudinal tube portion  31   d,  and an extending portion  31   e.  The first vertical tube portion  31   b  extends substantially vertically and downward from a connection portion  31   a  connected to the cylinder head  20   c.  The transverse tube portion  31   c  extends rearward below the second floor  9  from a lower end of the first vertical tube portion  31   b.  The second longitudinal tube portion  31   d  extends in such a manner as to elevate upward from a rear end of the transverse tube portion  31   c.  The extending portion  31   e  extends rearwardly from an upper end of the second longitudinal tube portion  31   d  through a space between the second seat  7  and a rear wheel drive shaft  5   a  of the rear wheels  5 . The exhaust pipe  31  includes a muffler  36  that is disposed in connection to a rear end of the extending portion  31   e  and is disposed so as to be located rearward of the second seat  7 . The muffler  36  has a substantially ellipsoidal shape having a front-back direction dimension greater than a vertical direction dimension, and the axis line thereof is arranged in the vehicle width direction. 
         [0033]    The intake pipe  30  is connected to the cylinder head  20   c  by way of a throttle body  32  equipped with a fuel injection valve  33 . A surge tank  34  is interposed midway of the intake pipe  30 . The surge tank  34  is disposed frontward of the engine  20  in the tunnel portion  24 . An air cleaner  35  is connected to the surge tank  34  by way of an intake air introduction pipe  30   a . The surge tank  34  has a volumetric capacity greater than a volumetric capacity of the air cleaner  35 . 
         [0034]    The air cleaner  35  is disposed in a central portion in the vehicle width direction. As viewed from the side, the air cleaner  35  is disposed between the partition wall  23  in the front compartment B and the hood  25 . An intake port  35   a  is connected and formed to a rear wall of the air cleaner  35 . The intake port  35   a  is located higher than upper ends  4   b  of the respective front wheels  4 , and is opened towards the rear side in the front compartment B. 
         [0035]    The continuously variable transmission  21  includes a transmission case  21   a,  a drive pulley  21   b,  a driven pulley  21   d,  and a V belt  21   e.  The transmission case  21   a  is integrally coupled to a left side in the vehicle width direction of the engine  20  and extends frontward from the engine  20 . The drive pulley  21   b  is housed in the transmission case  21   a  and is mounted to the crankshaft  20   a  of the engine  20 . The driven pulley  21   d  is mounted to an output shaft  21   c  parallel to the crankshaft  20   a.  The V belt  21   e  is wound around the drive pulley  21   b  and the driven pulley  21   d.    
         [0036]    Front and rear power transmission shafts  22   a  and  22   b  disposed towards the front-back direction are connected to the output shaft  21   c.  The front and rear power transmission shafts  22   a  and  22   b  are, respectively, connected to front and rear wheel drive shafts  4   a  and  5   a  via front and rear differential unit  22   c  and  22   d.    
         [0037]    The cooling unit  28  includes a cooling air introduction duct  40  that introduces cooling air into the continuously variable transmission  21 , and a cooling air discharge duct  41  that discharges air after cooling. The cooling air introduction duct  40  is routed towards the vehicle&#39;s forward side from the transmission case  21   a.  An air inlet  40   a  of the cooling air introduction duct  40  is located higher than the upper ends  4   b  of the front wheels  4  (same herein below), and is opened in the vicinity of a right wall of the air cleaner  35  in the vehicle width direction in the front compartment B. The cooling air discharge duct  41  is routed towards the vehicle front side from the transmission case  21   a.  An air outlet  41  a of the cooling air discharge duct  41  is located higher than the upper edges  4   b  of the front wheels  4 , and is opened downward and rearward in the front compartment B. 
         [0038]    The left and right front wheels  4  are supported by the vehicle body frame  2  via front wheel suspension systems  37  so as to be vertically and pivotally moveable. The left and right front wheel suspension systems  37  respectively are connected to the front frame  2   c , and include upper and lower arm members  38   a  and  38   b  that supports the front wheels  4  to be vertically and pivotally, and rotatably moveable, and cushion units  39  that interconnects between the upper arm members  38   a  and the front frame  2   c.    
         [0039]    The front frame  2   c  includes a first front cross frame  45 , a second front cross frame  46 , a first front side frame  47 , and a second side frame  48 . The first front cross frame  45  is disposed frontward of passenger compartment A higher than the main frame  2   a , and extends along the vehicle width direction. The second front cross frame  46  is disposed forward of and lower than the first front cross frame  45 , and extends along the vehicle width direction. The first and second front side frames  47  and  48 , respectively, are disposed so as to extend in the front-back direction on the left and right side in the vehicle width direction, and interconnect the first and the second front cross frames  45  and  46  forming a protective environment for radiator  19 . 
         [0040]    The front frame  2   c  further includes left and right front pillar members  50  and left and right rear pillar members  51  that, respectively, extend upward from left and right center members  12  of main body frame  2   a  to interconnect with first and second front side frames  47  and  48   
         [0041]    As shown in  FIG. 4 , the various frame members of front frame  2   c  are of differing height to provide an inclined upper frame profile. In application, first and second frit side frames  47  and  48  incline from a lowest point at their respective interconnections with front pillar members  50  to their highest point at their interconnection with first frame cross frame  45 . Along their respective lengths, second front cross frame is elevated in relation with front the front pillars and the rear pillars are elevated with respect to second front frame member. 
         [0042]    In application, the first front cross frame  45  is formed of an angular pipe, and the left and right end portions thereof are respectively connected to the left and right pillar members  15 . A steering support bracket  45   a  for supporting the steering wheel  17  is connected to the left end portion of the first front cross frame  45 . 
         [0043]    The respective first and second front side frames  47  and  48  are formed of an angular pipe, and a rear end portion thereof is connected to the first front cross frame  45  and extends linearly along a frontward and downward direction from the first front cross frame  45 . In other words, the respective first and second front side frames  47  and  48  are disposed to extend rearward and upward so that a portion located more rearward in the vehicle front-back direction is located higher. 
         [0044]    The second front cross frame  46  has a U-shaped cross section that is downwardly opened, and is connected to front end portions of the respective first and second front side frames  47  and  48 . Left and right end portions  46   a L,  46   a R of the second front cross frame  46 , respectively, protrude outward in the vehicle width direction from the first and the second front side frames  47  and  48 . 
         [0045]    As shown in  FIG. 5 , to provide further support to second front cross frame  46 , left and right front side members  52  and  53  extend along the front-back direction and are disposed on the outer sides of the first and the second front side frames  47  and  48  in the vehicle width direction. First and second front side frames  47  and  48  are inclined and in the preferred embodiment are inclined up to an angle of sixty-eight degrees as measured against a vertical axis along its length. The left and right side members  52  and  53 , respectively, have rear end faces connected to the first front cross frame  45  and front end portions connected to the left and right end portions  46   a  of the second front cross frame  46 . 
         [0046]    The left and right front side members  52  and  53 , respectively, are located at the same heights as the first and the second front side frames  47  and  48 , and are disposed so that the vehicle widthwise distance becomes narrower towards the vehicle front side. 
         [0047]    As shown in  FIG. 5 , a vehicle widthwise distance P 1  between the left and right center members  12  is set smaller than a vehicle widthwise distance P 2  between the first and the second front side frames  47  and  48 . This arrangement enables increasing arm lengths of the respective upper and lower arm members  38   a  and  38   b  on the left and right sides. 
         [0048]    Further, with reference to  FIG. 5 , as viewed from the vehicle front side, the front differential unit  22   c  is disposed in such a manner as to bridge between the left and right center members  12 . It is formed in the manner that a vehicle-lateral dimension W 1  between the left and right center members  12  is smaller than a vehicle-lateral dimension W 2  inclusive of joint portions  22   e  of the front differential unit  22   c  to which the front wheel drive shaft  4   a  is connected. 
         [0049]    The front frame  2   c  further includes first and second brackets  46   b,    46   b  respectively provided near connection portions of the second cross frame  46  with the first and the second side frames  47  and  48 . The first and second brackets  46   b,    46   b,  respectively, are formed integrally with left and right end portions  46   a  of the second cross frame  46 . Upper end portions  39   a  of the left and right cushion units  39  are, respectively, connected to the first and the second brackets  46   b.    
         [0050]    As shown in  FIG. 5 , the respective first and second front cross frames  45  and  46  in combination with first and second front side frames  47  and  48  define a radiator cage having an interior. Radiator  19  is mounted in a manner wherein it is located inside of a rectangular space B′ surrounded by the first and second front cross frames  45  and  46  and the first and second front side frames  47  and  48 . As is shown by the drawings, a key aspect of the radiator cage is that the radiator does not extend forwardly past the most outer structural surface area of second cross frame  46  and hence is protected from a frontal impact. Radiator  19  is configured as described in detail below. 
         [0051]    The radiator  19  is a vertical type radiator that includes a core  55 , an upper head tank  56 , and a lower head tank  57 . The core  55  has a rectangular shape in which the vertical dimension is greater than the vehicle widthwise dimension. The upper head tank  56  is connected to an upper end of the core  55 , and temporarily stores coolant that is used to cool the engine  20 . The lower head tank  57  is connected to a lower end of the core  55 , temporarily stores the coolant cooled when flowing through the core  55 , and returns the coolant into the engine  20 . By providing the upper head tank  56  and the lower head tank  57 , the coolant can be flown evenly into the overall area of the core  55 . A radiator cap  56   a  for opening and closing a filler port for the coolant is fitted to the upper head tank  56 . As shown in  FIG. 4 , an electric fan  58  is disposed on a rear face of the core  55 . 
         [0052]    As shown in  FIGS. 5 and 6 , radiator brackets  59  are mounted to left and right side portions of the upper tank  56 , respectively. The left and right radiator brackets  59  are, respectively, fixed with bolts to the first and the second front side frames  47  and  48 . Thereby, the upper portion  19   a  of the radiator  19  is supported by the first and the second front side frames  47  and  48 . 
         [0053]    As shown in  FIGS. 4 and 7 , a radiator projection portion  57   a  projecting downward is formed to the lower head tank  57 . A fixing bracket  62  extending rearward to fix the front differential unit  22   c  is mounted to the front pillar members  50 , and an upward U-shaped fixing bracket  60  which faces upward is fixed together with the fixing bracket  62 . A supporting hole  60   a  is formed in a bottom portion  60   b  of the fixing bracket  60 , and a grommet  61  is mounted to the supporting hole  60   a.  The protruding portion  57   a  is inserted into the supporting hole  60   a  with the grommet  61  interposed there between. Thereby, a lower portion  19   b  of the radiator  19  is resiliently supported by the front frame  2   c  via a fixing bracket  60  so as not to be moveable along the front-back and lateral directions. 
         [0054]    The radiator  19  is disposed in a manner that the upper portion  19   a  thereof is located rearward of and near the second front cross frame  46  and projects upward from the first and the second front side frames  47  and  48 . The hood  25  is located upward of and near the upper head tank  56 . 
         [0055]    Further, the radiator  19  is disposed in a manner that the lower portion  19   b  thereof is located downward of the second front cross frame  46 , and the upper portion  19   a  is located rearward of the second front cross frame  46 . More specifically, the radiator  19  is disposed in a rearwardly inclined state where a portion thereof is located more rearward as it is located more upward. While the invention is intended to providing for the inclination of the radiator from even a small five degree incline, in the preferred embodiment, radiator  19  is able to be inclined preferably at an angle up to fifteen degrees as measured against a vertical axis. Thereby, as viewed from the vehicle lateral side, the upper portion  19   a  of the radiator  19  is rearwardly inclined so brackets  59  may join them with first and the second front side frames  47  and  48 . 
         [0056]    According to the present embodiment, the upper portion  19   a  of the radiator  19  is disposed inside the rectangular space B′. The rectangular space B′ is surrounded by the second and first front cross frames  46  and  45 , which extend in the vehicle width direction and are disposed in the front and rear portions spaced apart from each other ahead of the passenger compartment A, and the first and the second front side frames  47  and  48 , which extend along the vehicle front-back direction and interconnect the first and the second front cross frames  45  and  46 . Hence, the first and the second front cross frames  45  and  46  and the first and the second front side frames  47  and  48  function as protection members. This enhances the protection performance of the radiator  19  against external forces exerted from both the vehicle lateral sides and vehicle front side. 
         [0057]    As described above, the first and the second brackets  46   b,    46   b  respectively, for supporting the upper end portions  39   a  of the cushion units  39  are provided near the connection portions of the second cross frame  46  with the first and the second front side frames  47  and  48 . Hence, input power transmitted from the front wheels  4 L and  4 R via the left and right cushion units  39  can be supported by the entirety of the front frame  2   c  having a high stiffness, consequently enabling enhancing the support stiffness of the cushion units  39 . This is accomplished as the upper end portions  39   a  are provided near the connection portions then first and second side frames  47  and  48  can assist in the support. If end portions  39   a  were not provided near the connection portions, then side frames  47  and  48  could not provide much support. 
         [0058]    Further, since the first and the second brackets  46   b,  respectively, are formed integral with the second front cross frame  46 , the number of parts is not increased, therefore enabling inhibiting costs from increasing. 
         [0059]    In the present invention, the configuration may be such that the first and the second brackets  46   b  are formed independently of the second front cross frame  46 , and are disposed near the connection portions of the second front cross frame  46 . 
         [0060]    In the present embodiment, the radiator  19  is disposed in a manner that the lower portion  19   b  thereof is located downwardly of the second front cross frame  46 , and the upper portion  19   a  thereof is located rearward of the second front cross frame  46 . As viewed from the vehicle lateral side, the radiator  19  is disposed in the rearwardly inclined state in which the upper portion  19   a  thereof is located more rearward as it is located more upward; that is, the lower portion  19   b  thereof is more frontward as it is located more downward. Consequently, the vertical dimension of the radiator  19  can be increased, and hence the cooling performance can be improved corresponding thereto. More specifically, since the hood  25  is located near the upper portion of the radiator  19 , in the case where, for example, the radiator  19  is disposed upright, the vertical dimension thereof has to be reduced to prevent interference with the hood  25 . In the present embodiment, the radiator  19  is rearwardly inclined, so that the size of the radiator  19  can be increased. 
         [0061]    In the present embodiment, the radiator  19  is disposed to diagonally intersect with the first and the second front side frames  47  and  48 . From this respect as well, the size of the radiator  19  can be increased, thereby enabling the cooling performance to be enhanced. 
         [0062]    In the present embodiment, the radiator  19  is the vertical type radiator in which the upper and lower head tank  56  and  57  are, respectively, connected to the upper and lower ends of the core  55 . Further, the lower head tank  57  is resiliently supported by means of the fixing bracket  60  of the front frame  2   c.  Consequently, the size of the radiator  19  can be increased while preventing interference with the hood  25 , and hence the cooling performance can be improved. In other words, it is more advantageous in terms of the cost to increase the radiation area size by increasing the core length rather than increasing the number of cores. In the present embodiment, since the radiator  19  is of the vertical type, the radiation area size can be increased by increasing the core length. 
         [0063]    In the present embodiment, the first and the second front side frames  47  and  48  are each inclined upwardly in an upward direction towards the vehicle rear so that it is positioned higher as it comes nearer to the vehicle rearward direction. Consequently, the inclination angle of the radiator  19  can be increased while preventing the interference with the hood  25 , and the size of the radiator  19  can be increased corresponding thereto.