Patent Publication Number: US-7213542-B2

Title: Saddle riding type vehicle

Description:
BACKGROUND OF THE INVENTION 
     Cross-Reference to Related Applications 
     The present application claims priority under 35 USC 119 to Japanese Patent Application No. 2003-337645 filed on Sep. 29, 2003 the entire contents of which are hereby incorporated by reference. 
     1. Field of the Invention 
     The present invention relates to a saddle riding type vehicle having a cooling fan and a radiator for engine oil cooling disposed in front of an engine. 
     2. Description of Background Art 
     A saddle riding type vehicle is a four-wheel vehicle that is capable of being driven on uneven roads. A seat is provided at the top center with an engine disposed under the seat and a steering handle provided in front of the seat. In addition, a four-wheel-drive mechanism is provided for propelling the vehicle. A driver will sit astride the seat for driving. Generally, the engine is cooled by natural air cooling. A cooling fan for forced cooling may be provided in front of the engine. 
     It is known that a conventional saddle riding type vehicle having a cooling fan uses the cooling fan to cool an oil cooler as well as the engine. See, Japanese Utility Model Appln. Laid-Open Publication No. 1-139022. 
       FIG. 9  in the drawings corresponds to  FIG. 1  in Japanese Utility Model Appln. Laid-Open Publication No. 1-139022. 
     A saddle riding type four-wheel vehicle  1  in Japanese Utility Model Appln. Laid-Open Publication No. 1-139022 includes front wheels  10  and a steering handle  9  provided at the front with a seat  19  disposed at the top center and an engine  13  that is mounted at the bottom. An engine cooling system is provided that includes a cooling fan  22  provided in front of the engine  13  and an oil cooler (heat exchanger)  23  provided adjacent to a lower half of the cooling fan  22 . An upper part of the engine can be cooled by air supplied from an upper half of the cooling fan  22 . 
     Special consideration is needed to be made with respect to the adhesion of dirt when the oil cooler (heat exchanger)  23  is disposed in front of the engine like the saddle riding type vehicle in Japanese Utility Model Appln. Laid-Open Publication No. 1-139022. 
     The configuration of the engine cooling system in Japanese Utility Model Appln. Laid-Open Publication No. 1-139022 uses many members such as a front pipe  7  in front of the oil cooler  23 . To further improve output, for example, it is necessary to relatively increase the size of the oil cooler  23 . In this case, cooling air supplied to the engine may decrease. 
     SUMMARY AND OBJECTS OF THE INVENTION 
     It is an object of the present invention to provide a saddle riding type vehicle designed to decrease adhesion of dirt to a radiator, miniaturize the radiator in front of an engine, and improve engine cooling performance by efficiently applying cooling air to the engine. 
     The present invention includes a saddle riding type vehicle which disposes an engine between front and rear wheels, forcedly cools the engine using a cooling fan disposed in front of the engine, cools engine oil using an externally disposed radiator, and covers the engine, radiator, and front wheels using a front cover. A rider will sit astride a seat provided above the engine for driving the vehicle. The radiator includes a first radiator and a second radiator wherein the first radiator is disposed in front of the engine and the second radiator is disposed in the front cover at a position higher than an upper edge of the front wheel. 
     The present invention includes the first radiator that is disposed immediately in front of the cooling fan. 
     The present invention includes the first radiator that is disposed so as to close an air intake guide of the cooling fan 50% or less. 
     The present invention includes the first and second radiators that are serially disposed along an oil line. 
     The present invention includes a heat radiation area of the second radiator that is greater than that of the first radiator. 
     The present invention includes an air intake channel that also used as a mud guard is provided in front of the second radiator. 
     According to the present invention, the radiator includes the first radiator and the second radiator. The first radiator is disposed in front of the engine. This makes it possible to miniaturize the first radiator. The cooling fan is disposed in front of the engine and generates wind that is efficiently applied to the engine. Thus, an advantage is provided to make it possible to improve the cooling performance of the engine. 
     The second radiator is disposed in the front cover at a position higher than the upper edge of the front wheel. The second radiator is less easily subject to adhesion of dirt and submersion under water than the first radiator. 
     According to the present invention, the first radiator is configured to be disposed immediately before the cooling fan. The first radiator can be exposed to wind generated by the cooling fan. It is possible to improve the cooling performance when the saddle riding type vehicle is operating a slow speeds or stops. 
     According to the present invention, the first radiator is disposed so as to close the air intake guide of the cooling fan less than 50%. 
     Closing the air intake guide greater than or equal to 50% decreases the amount of air supplied to the engine. When the saddle riding type vehicle is operating a slow speeds or stops, the engine&#39;s cooling performance degrades. 
     Closing the air intake guide less than 50% can reliably use 50% or more of the air intake guide to cool the engine. As a result, the cooling air is reliably applied to the engine, making it possible to improve the engine cooling performance. 
     According to the present invention, the first radiator and the second radiator are serially disposed along the oil line. Consequently, engine oil can be reliably supplied to both the first and second radiators. The first and second radiators can radiate the heat of the engine oil to the atmosphere. 
     Since the first and second radiators are serially disposed along the oil line, neither of the first and second radiators need to use branch pipes. Thus, the connection between the pipes does not become complicated and the number of hours of labor for connecting the pipes is decreased. 
     According to the present invention, the heat radiation area of the second radiator is larger than that of the first radiator. The second radiator can ensure heat radiation even if dirt adheres to the first radiator disposed in front of the engine to degrade the heat radiation performance of the first radiator. As a result, the radiator function can be maintained. 
     According to the present invention, the air intake channel is also used as a mud guard and is provided in front of the second radiator. Therefore, it is possible to more reliably guide the wind during operation from the front cover&#39;s opening to the second radiator. 
     The air intake channel also functions as a mud guard. The use of the air intake channel provides an advantage of preventing dirt from easily adhering to the second radiator. 
     Further scope of applicability of the present invention will become apparent from the detailed description given hereinafter. However, it should be understood that the detailed description and specific examples, while indicating preferred embodiments of the invention, are given by way of illustration only, since various changes and modifications within the spirit and scope of the invention will become apparent to those skilled in the art from this detailed description. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       The present invention will become more fully understood from the detailed description given hereinbelow and the accompanying drawings which are given by way of illustration only, and thus are not limitative of the present invention, and wherein: 
         FIG. 1  is a side view of the saddle riding type vehicle according to the present invention; 
         FIG. 2  is a front view of the saddle riding type vehicle according to the present invention; 
         FIG. 3  is a cross-sectional view taken along the line  3 — 3  of  FIG. 1 ; 
         FIG. 4  is a perspective view taken in the direction of the arrow  4  of  FIG. 1 ; 
         FIG. 5  is a perspective view of piping for the radiator used for the saddle riding type vehicle according to the present invention; 
         FIG. 6  is an operation diagram of the radiator used for the saddle riding type vehicle according to the present invention; 
         FIG. 7  is a side view of another embodiment; 
         FIG. 8  is a perspective view taken in the direction of the arrow  8  of  FIG. 7 ; and 
         FIG. 9  is a reproduction of  FIG. 1  in paten JP 1-139022. 
     
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
     The best mode for carrying out the invention will be described with reference to the accompanying drawings. Horizontal and vertical directions of the drawings are based on a direction along which the reference numerals are described. 
       FIG. 1  is a side view of a saddle riding type vehicle according to the present invention. A saddle riding type vehicle  10  includes a body frame  11 , an engine  12  mounted at the top center of the body frame  11  and a transmission system  13  connected to the engine  12  and mounted on the body frame  11 . A suspension system  14  (having front and rear suspensions  15  and  16 ) oscillatably holds the front and the rear of the transmission system  13 , on the body frame  11 . Front wheels  17  (see  FIG. 2 ) are mounted on the right and the left in front of the transmission system  13 . Rear wheels  18  (see  FIG. 2 ) are mounted on the right and the left in the rear of the transmission system  13 . A steering system  21  is coupled to the front wheels  17  and is mounted on the body frame  11 . A fender  22  is mounted on the body frame  11 . A rider M can sit astride a seat  33  provided over the engine  12  for driving the vehicle. 
     The body frame  11  includes a main frame  25  with front and rear frames  26  and  27  mounted on the front and the rear of the main frame  25 . A bracket  31  is mounted between the right and the left under the front frame  26  with a cross member  32  mounted between the right and the left above the front frame  26 . A seat  33  is mounted on the main frame  25 . A fuel tank  34  is provided together with a front guard  35  mounted on the front frame  26 . A front carrier  36  is mounted on the front frame  26  and a rear carrier  37  is mounted on the rear of the main frame  25 . 
     The suspension system  14  is based on an independent suspension. A front suspension  15  includes a front arm  41  oscillatably mounted on the body frame  11  with a shock absorber  42  mounted between the front arm  41  and the cross member  32  and a coil spring  43 . A rear suspension  16  has a shock absorber  44  mounted on the body frame  11 . A center shaft line  45  of the front wheel  17  is provided. 
     The transmission system  13  includes a transmission  47  capable of four-wheel driving, a gear change pedal  48 , front and rear drive axles  51  and  52  coupled to the front and the rear of the transmission  47 , a front final deceleration system  53  coupled to the front drive axle  51  and mounted on the front arm  41  and a rear final deceleration system  54  coupled to the rear drive axle  52 . 
     The steering system  21  includes a steering shaft  56  mounted on the top front of the main frame  25  by means of a shaft holder  55  and a handle  57  mounted on the steering shaft  56 . 
     The fender  22  includes a front cover  61  and a rear cover  62 . The front cover  61  will be described later. 
     The engine  12  is a four-cycle engine and includes a cylinder block  63 , a cylinder head  64  mounted on the cylinder block  63 , an exhaust system  65  connected to the front, a carburetor  66  mounted on the rear, a valve train  67  provided in the cylinder head  64 , a piston  71  moving in the cylinder block  63 , a crankshaft  72  coupled to the piston  71 , an oil pan  73  disposed under the cylinder block  63 , a cooling fan  74  disposed in front of the engine  12  to forcedly air-cool the engine and a lubrication mechanism  75 . 
     The cooling fan  74  includes an electric motor  77  at the center of an air intake guide  76  with fan  78  attached to the electric motor  77 . The electric motor  77  rotates the fan  78  based on information from a control system (not shown). The right and the left of the air intake guide  76  are fixed to the main frame  25  with lugs  81  (see  FIG. 3 ). 
     The lubrication mechanism  75  supplies engine oil  82  to transmission gears of the transmission  47 , the valve train  67 , and the crankshaft  72 . The lubrication mechanism  75  includes an oil strainer  83  disposed in the oil pan  73 , an oil pump  84 , an oil filter  85  (see  FIG. 5 ) and an oil cooler  86  as a radiator. 
     The oil cooler (radiator)  86  includes a first oil cooler  91  as a first radiator and a second oil cooler  92  as a second radiator. The first oil cooler (first radiator)  91  is disposed in front of the engine  12 . The second oil cooler (second radiator)  92  is disposed in the front cover  61  at a position higher than an upper edge  93  of the front wheel  17 . The engine oil  82  is air-cooled. 
     The first oil cooler (first radiator)  91  is disposed immediately in front of the cooling fan  74 . 
     The second oil cooler (second radiator)  92  is disposed almost immediately above the center shaft line  45  of the front wheel  17 . 
     Depending on design conditions and the like, the second oil cooler (second radiator)  92  may be positioned forward (toward arrow a) or backward (toward arrow b) of the center shaft line  45  of the front wheel  17 . 
     The front cover  61  covers the engine  12 , the oil cooler (radiator)  86  and the front wheel  17 . The front cover  61  is provided with right and left headlamps  94  (see  FIG. 2 ). A first opening  95  is formed at the bottom center. A second opening  96  is formed at the rear of the first opening  95 . A grille  97  is fit into the second opening  96 . 
       FIG. 2  is a front view of the saddle riding type vehicle according to the present invention. 
     As mentioned above, the saddle riding type vehicle  10  forcedly air-cools the engine  12  (see  FIG. 1 ) by using the cooling fan  74  disposed in front of the engine. The externally disposed oil cooler  86  is used to cool the engine oil  82  (see  FIG. 1 ). The saddle riding type vehicle  10  is configured to cover the engine, the oil cooler  86  and the front wheels  17  with the front cover  61 . 
     As mentioned above, the oil cooler  86  is a radiator whose second oil cooler  92  is disposed in the front cover  61  at a position higher than the top edge  93  of the front wheels  17 . 
     The second opening  96  has an inlet channel  102  (bottom  103  and side walls  104 ) formed continuously with an external surface  101  of the front cover  61 . The second opening  96  guides air toward the second oil cooler  92  during driving and improves ventilation when the saddle riding type vehicle  10  stops. 
     The front guard  35  has a vertical member  105  and a horizontal member  106 . The vertical member  105  and the horizontal member  106  are mounted so as not to interfere with the first and second openings  95  and  96 . 
       FIG. 3  is a cross-sectional view taken along the line  3 — 3  of  FIG. 1  for illustrating the cooling fan  74  and the oil cooler  86  (the first oil cooler  91  and the second oil cooler  92 ). 
     The first and second oil coolers  91  and  92  have almost the same configuration as that of existing oil coolers. Brackets  107  are provided for mounting the second oil cooler  92  on the body frame  11  (see  FIG. 1 ). 
     The first oil cooler  91  is mounted on the body frame  11  (see  FIG. 1 ) with the lugs  81 . 
     The position of the first oil cooler  91  will now be described. 
     The first oil cooler  91  is disposed so as to close the air intake guide  76  of the cooling fan  74  less than 50%. More specifically, it is assumed that an inside diameter of the air intake guide  76  is Df and an area thereof is Af(Af=πDf 2 /4). The first oil cooler  91  is disposed so that the area Af of the air intake guide  76  will becomes less than 50%. 
     Closing the air intake guide  76  greater than or equal to 50% decreases the amount of air supplied to the engine  12  (see  FIG. 1 ). When the saddle riding type vehicle  10  is operating at a slow speed or stops, the engine&#39;s cooling performance degrades. 
     Closing the air intake guide  76  less than 50% can reliably use a half (50% or more) of the area Af of the air intake guide  76  to cool the engine. As a result, the cooling air is reliably applied to the engine, making it possible to improve the engine cooling performance. 
     In this example, the first oil cooler  91  is disposed at an upper half, i.e., above a center shaft  108  of the electric motor  77  for the cooling fan  74 . By contrast, the first oil cooler  91  may be disposed at a lower half. Further, depending on conditions, the first oil cooler  91  can be disposed at a left or right half against the center shaft  108 . 
     The following describes heat radiation areas for the first and second oil coolers  91  and  92 . 
     A heat radiation area of the second oil cooler  92  is configured to be larger than that of the first oil cooler  91 . With respect to the projected areas viewed from the front, a projected area of the second oil cooler  92  is apparently larger than that of the first oil cooler  91 . 
     This relation may be reversed depending on conditions. For example, the heat radiation area of the first oil cooler  91  can be made larger than that of the second oil cooler  92  so as to provide intended heat radiation performance under operating conditions. 
     The same heat radiation area may be used. When the heat radiation performance is available, the heat radiation area of the second oil cooler  92  may be the same as that of the first oil cooler  91 . 
       FIG. 4  is a perspective view taken in the direction of the arrow  4  of  FIG. 1  and shows the second oil cooler  92 , the grille  97 , the second opening  96  and the first opening  95 . 
     As mentioned above, the second opening  96  has the inlet channel  102 . The inlet channel  102  has the bottom  103  and the side walls  104  formed continuously with the external surface  101  of the front cover  61 . The inlet channel  102  is an air intake slot almost straight facing the second oil cooler  92 . 
     The grille  97  mainly aims at preventing foreign particles from entering and regulating air flow and may be formed in any configuration or design. 
       FIG. 5  is a perspective view of the piping of the radiator used for the saddle riding type vehicle according to the present invention.  FIG. 5  shows the oil cooler  86  as the radiator as well as a lubrication mechanism  75  (oil pump  84  and oil filter  85 ) and the first oil cooler (first radiator)  91  of the engine  12  disposed immediately in front of the cooling fan  74 . 
     The lubrication mechanism  75  serially disposes the first oil cooler (first radiator)  91  and the second oil cooler (second radiator)  92  along the oil line  109 . The oil line  109  represents the whole of lubrication routes. First through third pipes  111  through  113  are used to serially connect the first and second oil coolers  91  and  92 . More specifically, one end of the first pipe  111  is connected to an outlet  115  of the oil filter  85 . The other end of the first pipe  111  is connected to an inlet  116  of the second oil cooler  92 . One end of the second pipe  112  is connected to an outlet  118  of the second oil cooler  92 . The other end of the second  112  is connected to an inlet  121  of the first oil cooler  91 . One end of the third pipe  113  is connected to an outlet  122  of the first oil cooler  91 . The other end of the third pipe  113  is connected to a supply port  123 . 
     The following partly summarizes a flow of engine oil  82 . 
     The engine oil  82  is ejected from the oil pump  84 , passes through a filter body  124  of the oil filter  85  and once exits from the outlet  115  of the oil filter  85 . The engine oil  82  then flows through the first pipe  111  as indicated by the arrow d, further flows through the second oil cooler  92 , the second pipe  112 , the first oil cooler  91  and the third pipe  113  in order and then is supplied to the above-mentioned parts from the supply port  123 . 
     While the engine oil has been described as cooling fluid cooled by the radiator, cooling fluids other than the engine oil can include water for a water-cooled system. Water used for the water-cooled system includes water for a water-cooled engine, a water-cooled oil cooler and water-cooled electric parts. 
     The following describes the effects of the radiator used for the above-mentioned saddle riding type vehicle. 
       FIG. 6  is an operational diagram of the radiator used for the saddle riding type vehicle according to the present invention. 
     The oil cooler  86  includes the first oil cooler  91  and the second oil cooler  92 . The first oil cooler  91  is disposed at the rear of the engine  12 . This makes it possible to miniaturize the first oil cooler  91 . The cooling fan  74  is disposed in front of the engine  12  and generates wind that is efficiently applied to the engine. Thus, it is possible to improve the cooling performance of the engine  12 . 
     In the oil cooler  86 , the second oil cooler  92  is disposed in the front cover  61  at a position higher than the upper edge  93  of the front wheel  17 . The second oil cooler  92  is less easily subject to adhesion of dirt and submersion under water than the first oil cooler  91 . 
     The first oil cooler  91  is configured to be disposed immediately before the cooling fan  74 . The first oil cooler  91  can be exposed to wind generated by the cooling fan  74  as indicated by the arrow e. Thus, it is possible to improve the cooling performance of the oil cooler  86  when the saddle riding type vehicle  10  is operating at slow speeds or stops. 
     The first oil cooler  91  is disposed so as to close the air intake guide  76  of the cooling fan  74  less than 50%. Accordingly, it is possible to reliably use 50% or more of the air intake guide  76  for cooling the engine. As a result, the cooling wind can be reliably applied to the engine  12  to improve the engine&#39;s cooling performance. 
     As shown in  FIG. 5 , the first oil cooler  91  and the second oil cooler  92  are serially disposed along the oil line  109 . Consequently, engine oil can be reliably supplied to both the first and second oil coolers  91  and  92 . The first and second oil coolers  91  and  92  can radiate the heat of the engine oil to the atmosphere. 
     Since the first and second oil coolers  91  and  92  are serially disposed along the oil line  109 , the each of the first and second oil coolers  91  and  92  do not need to use branch pipes that are needed for a parallel connection. Thus, the connection between pipes does not become complicated and the labor hours for connecting the pipes is decreased. 
     As shown in  FIG. 3 , the heat radiation area of the second oil cooler  92  is larger than that of the first oil cooler  91 . The second oil cooler  92  can ensure heat radiation even if dirt adheres to the first oil cooler  91  disposed in front of the engine to degrade the heat radiation performance of the first oil cooler. As a result, the radiator function can be maintained. 
       FIG. 7  is a side view of another embodiment. The mutually corresponding parts in  FIGS. 7 and 1  are designated by the same reference numerals and a detailed description is omitted for simplicity. 
     A front cover  61 B covers the engine  12 , the oil cooler (radiator)  86  and the front wheels  17 . The front cover  61  is provided with right and left headlamps  94  (see  FIG. 2 ). The first opening  95  is formed at the bottom center. The second opening  96  is formed at the rear of the first opening  95 . The grille  97  is fit into the second opening  96 . An air intake channel  98  which also functions as a mud guard is provided at the rear of the grille  97  and in front of the second oil cooler (second radiator)  92 . 
       FIG. 8  is a perspective view taken in the direction of the arrow  8  of  FIG. 7 . The mutually corresponding parts in  FIGS. 8 and 4  are designated by the same reference numerals and a detailed description is omitted for simplicity. 
     The air intake channel  98  has an angled U-shaped cross-sectional view and can more reliably guide the wind during operation of the vehicle from the rear of the second opening  96  to the second oil cooler  92 . 
     The air intake channel also functions as a mud guard. The use of the air intake channel prevents dirt from easily adhering to the second oil cooler  92 . 
     More particularly, the air intake channel  98  can prevent scattered things such as gravel stones from easily hitting against the second oil cooler  92 . 
     While the embodiments of the saddle riding type vehicle according to the present invention are applied to four-wheel vehicles, the saddle riding type vehicle can be also applied to three-wheel and two-wheel vehicles as well as general vehicles. 
     The saddle riding type vehicle according to the present invention is suitable for four-wheel vehicles. 
     The invention being thus described, it will be obvious that the same may be varied in many ways. Such variations are not to be regarded as a departure from the spirit and scope of the invention, and all such modifications as would be obvious to one skilled in the art are intended to be included within the scope of the following claims.