Abstract:
A chassis frame for a vehicle such as a motorcycle is provided with an engine mounted at the chassis frame and an engine guard near the engine spaced apart between chassis frame and the engine to protect the engine. The engine guard protrudes toward the chassis frame. An inclined surface is formed inside the chassis side of the engine guard so as to be oppositely faced against the engine, and an air guide passage is formed between the inclined surface and the engine. During operation of the vehicle, the air or wind passes through the air guide passage to enhance the cooling of the engine. The aforementioned arrangement prevents the disturbance or prohibition of the flow of engine cooling air during operation of the motorcycle while also enabling a relatively high degree of freedom in design with respect to an outer appearance of the engine guard and vehicle.

Description:
CROSS-REFERENCES TO RELATED APPLICATIONS 
   This nonprovisional application claims priority under 35 U.S.C. § 119(a) on Patent Application No. 2002-245855 filed in Japan on Aug. 26, 2002, the entirety of which is herein incorporated by reference. 
   BACKGROUND OF THE INVENTION 
   1. Field of the Invention 
   The present invention relates to an air guide device in a vehicle, and more particularly for an air guide device in a motorcycle. 
   2. Description of the Background Art 
   Japanese Utility Application Model Laid-Open No. Sho 60-85291 provides an exemplary description of a motorcycle in which an engine guard is arranged near an engine to protect the engine while also being spaced apart from the engine. The engine guard protrudes toward the side of the motorcycle chassis. However, the present inventors have determined that the motorcycle described in the above document suffers from the following problems. 
   In the aforesaid motorcycle, the engine guard is made by bending or working a pipe member having a circular sectional shape. The pipe member having a circular sectional shape is selected since it has the advantage of not prohibiting the flow of air or wind, e.g., contributing to more efficient cooling of the engine. However, the circular shaped pipe member has some disadvantages during the bending process when a bending work is carried out and a member of optional shape cannot be attained. Accordingly, the engine guard made by the pipe member having a circular sectional shape is limited in its variations in design and orientation with respect to the engine. For example, the position of the fixing part is set at a certain location or the entire shape of the completed engine guard is limited to certain designs, e.g., it has a low degree of freedom in design. Further, when the pipe member having a circular sectional shape is used, the overall design and layout of the engine guard cannot be easily varied in its outer appearance. 
   Alternatively, if the engine guard is made with a plate member in lieu of the pipe member, either the fixing position of the plate member or the fixing angle of the engine guard may prohibit a flow of the wind contributing to cooling of the engine during vehicle operation. 
   SUMMARY OF THE INVENTION 
   The present invention overcomes the shortcomings associated with the background art and achieves other advantages not realized by the background art. 
   It is an object of the present invention to provide an air guide device, e.g., an engine guard, in a vehicle such as a motorcycle that does not prohibit a flow of engine cooling air during operation of the vehicle. 
   It is an object of the present invention to attain freedom in design and overall outer appearance of the air guide device. 
   One or more of these and other objects are accomplished by an air guide device for a vehicle comprising a chassis frame; an engine being mounted on the chassis frame; and an engine guard being arranged near the engine and protruding from the engine and the chassis frame spaced apart toward a side of the chassis frame so as to protect the engine, wherein an inner side of the engine guard at the chassis frame is formed with an inclined surface opposing an exterior surface of the engine. In this case, a relatively wide air guide passage is formed between the engine and the inclined surface of the engine guard and cooling of the engine is promoted by passing the running air through the air guide passage during its running operation. 
   One or more of these and other objects are further accomplished by an air guide device for a vehicle comprising a vehicle main body having a chassis frame and an engine; an accessory storage box being secured to a rear side of the vehicle main body; and an accessory storage box guard being arranged near the accessory storage box, the accessory storage box guard being spaced apart from the accessory storage box to protect the accessory storage box and protruding from a side of the chassis frame, wherein an inner side of the accessory storage box guard is formed with a flat surface opposing the accessory storage box and forming an air passage between the accessory storage box and the accessory storage box guard. In this case, a relatively wide air guide passage is formed between an accessory storage box fixed to the rear side of the vehicle main body and an inclined surface of the accessory storage box guard, the running wind after passing by the engine passes through the air guide passage and further runs toward the rear part of the vehicle, resulting in that the flow passage for cooling the engine is assured during its running operation. 
   One or more of these and other objects are further accomplished by an air guide device for a vehicle comprising a vehicle main body having a chassis frame and an engine; an accessory storage box being secured to a rear side of the vehicle main body; an accessory storage box guard being arranged near the accessory storage box, the accessory storage box guard being spaced apart from the accessory storage box to protect the accessory storage box and protruding from a side of the chassis frame, wherein an inner side of the accessory storage box guard is formed with a flat surface opposing the accessory storage box; and an engine guard being arranged near the engine and protruding from the engine and the chassis frame spaced apart toward a side of the chassis frame so as to protect the engine, wherein an inner side of the engine guard at the chassis frame is formed with an inclined surface opposing an exterior surface of the engine. 
   The air guide device may include a guard member(s) having an irregular-shaped sectional surface. In this case, since the guard member has an irregular-shaped sectional surface different from the circular sectional shape, it is possible to form either a flat surface or curved surface at a requisite location, resulting in flexibility of design. 
   The air guide device may also be formed by a bulge work, e.g., by molding. In this case, the guard member(s) of many types of shapes can be easily machined. 
   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 hereinafter 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 perspective view of a motorcycle according to a preferred embodiment of the present invention; 
       FIG. 2  is a side elevation of a motorcycle according to a preferred embodiment of the present invention; 
       FIG. 3  is a partial expanded side elevation of a motorcycle according to a preferred embodiment of the present invention; 
       FIG. 4  is a partial front elevation of an engine guard fixing part and an engine of a motorcycle according to a preferred embodiment of the present invention; 
       FIGS. 5(   a )– 5 ( b ) are perspective views of an engine guard of a motorcycle according to a preferred embodiment of the present invention; 
       FIG. 6  is a front elevation view for showing an engine guard of a motorcycle according to a preferred embodiment of the present invention; 
       FIG. 7  is a partial top plan view in section of an engine guard fixing part of a motorcycle and a part of an engine according to a preferred embodiment of the present invention; and 
       FIG. 8  is a schematic top plan view of a motorcycle according to a preferred embodiment of the present invention while the motorcycle is operating. 
   

   DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
   The present invention will hereinafter be described with reference to the accompanying drawings. An air guide or engine guard device in a vehicle will be described hereinafter with reference to an exemplary motorcycle. Accordingly, the description relating to forward or rearward, and rightward or leftward directions is based on a chassis of the motorcycle as the frame of reference. 
     FIG. 1  is a perspective view of a motorcycle according to a preferred embodiment of the present invention.  FIG. 2  is a side elevation of a motorcycle according to a preferred embodiment of the present invention. The motorcycle  1  is a so-called American type, wherein it has a chassis frame  2 , a link-type front suspension  3  rotatably supported at a front end of the chassis frame  2 , a headlight  4  arranged at an upper part of the link-type front suspension  3 , a pair of right and left blinkers  5  arranged below the headlight  4  of the link-type front suspension  3 , and a steering handle  6  fixed to an upper end of the link-type front suspension  3  and arranged at an upper part of the chassis front part. 
   In addition, this motorcycle  1  includes a front wheel  7  rotatably supported at the link-type front suspension  3 , a front fender  8  supported at the link-type front suspension  3  and covering the upper side of the front wheel  7 , an engine  9  mounted at the chassis frame  2 , a rear swing arm  11  slidably arranged around an axis extending along a lateral direction at the rear part of the chassis by the chassis frame  2 , a rear wheel  12  rotatably mounted at the rear end of the rear swing arm  11  and rotated with a driving force of the engine  9 , and a rear fender  13  supported by the chassis frame  2  and covering the upper side of the rear wheel  12 . The motorcycle  1  also includes a tear-drop shaped fuel tank  14  arranged at an upper part of the chassis frame  2 , a main seat  15  arranged at a rear part of the fuel tank  14  where a driver sits, a pair of right and left rear blinkers  17  arranged at a rear part of the rear fender  13 , and a license plate fixing part  19  arranged at the rear end of the rear fender  13 . 
   The chassis frame  2  includes a front frame  21  and a rear frame  22  each of which is arranged at a forward or a rearward part of the chassis frame  2 , respectively. The front frame  21  includes a front end head pipe  23 ; and an upper frame  24  divided from the head pipe  23  into a right segment and a left segment, and extending in a inclined, lower rearward direction and further extending rearwardly in a horizontal direction. A down frame  25  having a pair of right and left plate members with a substantial U-shape (as seen in a side elevational view) is welded to the rear end of the upper frame  22 , and extending rearwardly in a slightly inclined downward direction, rearwardly in a horizontal direction, then extending in a downward direction, and finally having a lower end extending in a forward direction. A plurality of connector members for connecting these pairs of right and left plate members are also provided in the front frame assembly  21 . 
   The rear frame  22  includes right and left upper pipes  26  connected to the upper rear end of the down frame  25  and extending upwardly therefrom. Right and left down pipes  27  are connected to the substantial central rear end along a height direction of the down frame  25 , and extend from the down frame  25  in a inclined, upper rearward direction, where these members are connected to the midway part of the upper pipe  26  and extending in a rearward horizontal direction. 
   The engine  9  is a horizontal, opposed type engine in which the right cylinder head, left cylinder head, right cylinder and left cylinder are arranged to be inclined outwardly to be oppositely faced to each other. The engine  9  is suspended by the engine hanger  28  formed at a lower part of the upper frame  24 , the engine hanger  29  formed at a lower surface of the upper part of the down frame  25  and the engine hanger  30  formed at a front end of the lower part of the down frame  25 . The rear swing arm  11  can be oscillated around a pivot  31  of the down frame  25  in a vertical direction with a base part of the front end being pivoted at the pivot  31  of the down frame. In addition, a rear suspension device  34  of a shock absorber unit  32  and the link mechanism  33  are placed between the rear swing arm  11  and the down frame  25 . Accordingly, the rear wheel  12  dampens and absorbs vibration transmitted from the road surface through the shock absorber unit  32  and the linked mechanism  33 . 
     FIG. 3  is a partial, expanded side elevation of a motorcycle according to a preferred embodiment of the present invention. As shown in  FIG. 3 , the side frame  35  is screw set to the side part of the engine  9  at its front and rear ends to the lower front end of the engine  9  and the lower front end of the down frame  25  and fixed to extend in a forward or rearward direction of the chassis. In addition, the engine guard  40  is arranged near the front part of the engine to protect the engine  9  while being spaced apart, and protruding outward from the side of the chassis and extended in an upward or downward direction. A radiator cover  41  is also shown in  FIGS. 1–2 . 
     FIG. 4  is a partial front elevation of an engine guard fixing part and an engine of a motorcycle according to a preferred embodiment of the present invention.  FIG. 5  is a perspective view of an engine guard of a motorcycle according to a preferred embodiment of the present invention.  FIG. 6  is a front elevation view for showing an engine guard of a motorcycle according to a preferred embodiment of the present invention. As shown in  FIGS. 4 to 6 , the engine guard  40  includes a hollow part  45  entirely formed into a substantial U-shape, solid fixing segments  46 ,  46  fixed at both ends of the hollow part  45  and filled with material inside, and a connecting pipe  47  connecting the fixing segments  46 ,  46  to each other. As shown in  FIG. 4 , the hollow part  45  includes a horizontal segment  48  extending in a horizontal direction to cover the upper part of the head cover  9   a  of the engine  9  when the engine cover  40  is fixed to the chassis, a vertical segment  49  curved to cross at a right angle with the horizontal segment  48  and extending in a vertical direction to cover the side part of the head cover  9   a , and an inclined segment  50  curved approximately 45° from the vertical segment  49  and extending in an inclined, downward direction to cover the lower part of the head cover  9   a . The hollow part  45  has an irregular sectional shape formed into a bulge work in which a certain pressure is applied inside the raw material under utilization of liquid to perform a bulged-out molding, wherein both ends are connected to the fixed segments  46 ,  46  formed by forging, e.g., through welding. In addition, the fixed segments  46 ,  46  and the connecting pipe  47  are also connected with welding. 
   A reinforcing pipe member  51  is embedded inside each of the horizontal segment  48  of the hollow part  45  and the inclined segment  50  while being fixed to the fixed segments  46  by a proper fixing method such as a welding and the like. The engine guard  40  having the aforesaid configuration is fixed to the chassis by a method wherein the threaded hole  46   a  formed at the upper fixed segment  46  coincides with a threaded hole integrally formed with the engine hanger  28  of the upper frame  24  and at the same time the threaded hole  46   b  formed at the lower fixed segment  46  coincides with the threaded hole formed at the side frame  35 . The threaded holes are used to fix the engine guard  40  to the chassis by bolts  43 ,  44  (refer to  FIGS. 3 and 4 ). 
     FIG. 7  is a partial top plan view in section of an engine guard fixing part of a motorcycle and a part of an engine according to a preferred embodiment of the present invention. As shown in  FIG. 7 , the preferred embodiment is made such that the vertical segment  49  of the hollow part  45  is formed into a trapezoid section with a major axis inclined in respect to the forward or rearward direction. With this arrangement, the vertical segment  49  is formed such that an inclined surface  52  is formed at a segment where it enters inside the chassis when it is fixed to the chassis. The inclined surface  52  is inclined such that it may oppositely face against the head cover  9   a  of the engine and it is expanded gradually outside the chassis as it is directed rearwardly of the chassis. 
   Thus, in accordance with the air guide and engine guard device of the motorcycle having the aforesaid configuration, the inclined surface  52  is formed to be oppositely faced against the head cover  9   a  of the engine  9  inside the chassis of the engine guard  40  and inside the chassis of the vertical segment  49  of the hollow part  45 . In particular, the inclined surface  52  of the vertical segment  49  forms the air guide passage Da between these elements together with the inclined surface  9   aa  of the cylinder head  9   a  of the engine  9 . Accordingly, when the motorcycle runs, the air striking against the front part of the engine  9  through the side part of the front wheel  7  flows through the air guide passage Da and rearwardly along the side part of the engine  9  so as to form a series of engine cooling airflows. 
   As described above, irrespective of an arrangement of the engine guard  40 , the engine guard  40  does not prohibit a flow of the running air contributing to the cooling of the engine  9 . In turn, in consideration of an effect of negative pressure when the running air flows at the side part of the chassis, the engine cooling air passing through the air guide passage Da is increased in its volume, resulting in that a cooling effect of the engine  9  under the running air can be increased. 
   In addition, since the major part of the engine guard  40  is not made by bending of the pipe member, but by bulge machining or molding, it becomes possible to form it into a relatively free shape. For example, a sectional surface is freely changed for every section to enable its strength to be high and enable a space in respect to the associated components positioned near the engine guard to be freely set. In addition, its outer appearance can be enhanced as desired by the manufacturer. 
   Although the aforesaid preferred embodiment include the inclined surface  52  oppositely facing against the engine  9  inside the chassis of the engine guard  40 , the present invention is not limited to this embodiment. In addition to forming of the inclined surface  52  at the engine guard  40 , it may also be applicable in the vehicle such as a motorcycle having the accessory storage box  61  fixed to the rear side of the vehicle main body  60  having the chassis frame and the engine as shown in  FIG. 8  that the inclined surface  63  is arranged at the accessory storage box guard  62  set near the accessory storage box  61 . 
   The accessory storage box guard  62  is provided spaced apart between it and the accessory storage box  61  and protruded toward the side of the chassis so as to protect the accessory storage box  61  fixed to the rear side of the vehicle main body  60 , and the inclined surface  63  may be formed inside the chassis side of the accessory storage box guard  62  so as to oppositely face against the accessory storage box  61 . 
     FIG. 8  is a schematic top plan view of a motorcycle according to a preferred embodiment of the present invention while the motorcycle is operating. In this case, as shown in  FIG. 8 , the wind or air passing by the engine  9  or the driver and co-passenger&#39;s legs  65 ,  66  flows through the relative wide air guide passage Db formed between the accessory storage box  61  and the inclined surface  63  of the accessory storage box guard  62  and is released to a rearward side of the vehicle. This results in an adequate air flow for engine cooling and the removal of hot air around the legs  65  of the driver can be assured. The present invention not only provides an effective cooling of the engine but also enables an air flow preferable for the driving environment, e.g., with respect to the driver. 
   In addition, although the preferred embodiment has been described in reference to the case of the motorcycle, the present invention is not limited to the motorcycle, but it can be applied to a three-wheeled vehicle or a buggy-type four-wheeled vehicle, such as an ATV (All-Terrain Vehicle). 
   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.