Abstract:
An air cleaner structure that is capable of achieving smooth air-intake capability while separating water contained in air to supply clean air to the engine side. A lower half member of an air-intake duct is, when viewed from above, provided with a central partition and partitions located symmetrically in the vicinity of the central partition, partitions located near both ends, and narrowing passages and widening passages surrounded by the partitions. Air enters from the front of the vehicle body and flows like eddy currents from outlet ports of the widening passages to the outlet ports of the narrowing passages like eddy currents. Thus, coarse particulate and dust contained in the air stay on the outlet port side of the air-intake duct.

Description:
BACKGROUND OF THE INVENTION 
     CROSS-REFERENCE TO RELATED APPLICATIONS 
     The present non-provisional application claims priority under 35 USC 119 to Japanese Patent Application No. 2003-376917 filed on Nov. 6, 2003 the entire contents thereof is hereby incorporated by reference. 
     FIELD OF THE INVENTION 
     The present invention relates to an air cleaner structure for a motorcycle. 
     DESCRIPTION OF BACKGROUND ART 
     An air cleaner for a motorcycle is a device having a function for reducing or removing water taken into the air cleaner when it rains, or for reducing an air-intake sound of an engine. 
     Therefore, an important performance of the air cleaner is how water contained in the intake air can be removed by an element constituting the air cleaner or in an air-intake duct, which is a passage for introducing outside air. 
     An air cleaner of a type which accumulates water contained in intake air or rainwater in a surge tank that is provided in an intake duct and discharges the water therefrom is proposed in, for example, Japanese Patent No. 2663251. 
     Referring now to  FIG. 7  of the present drawings that corresponds to a figure in Japanese Patent No. 2663251 an air cleaner  100  is a structure that is connected to an air-intake passage  101  provided below the air cleaner  100 . A carburetor  102  is provided below the air-intake passage  101  with an engine  104  being provided below an air-intake hole  103 . 
     The front portion of the air cleaner  100  includes an air intake port  105 , a surge tank  106 , an intake duct  107 , and an air-flow passage  108 . A drain  109  is provided for discharging water therefrom. 
     Outside air enters through the air-intake port  105  through the intake duct  107  the air-flow passage  108 , and enters the air cleaner  100 . In this process, water contained in the intake air is accumulated in the surge tank  106 . Outside air that enters into the air cleaner  100  enters from the air-intake passage  101  into the carburetor  102 , is converted into an air-fuel mixture, and is filled into the engine  104 . 
     The air cleaner  100  in Japanese Patent No. 2663251 is provided with a surge tank  106  on the upstream side of the intake duct  107 . The surge tank  106  separates rainwater or the like from the intake air. However, since the capacity of the surge tank  106  insignificantly large, there is a limit in the flexibility of designing the air cleaner. 
     SUMMARY AND OBJECTS OF THE INVENTION 
     Accordingly, it is an object of the present invention to provide an air cleaner structure which has flexibility in design and can achieve a smooth air-intake capability while keeping its function for separating rainwater or water contained in air. 
     The present invention provides an air cleaner structure to be mounted to a vehicle including an air-intake duct for introducing outside air provided at an inlet port of a cleaner case having an element for cleaning air integrated therein. The air intake duct includes partitions for partitioning the interior of the duct wherein the partitions are inclined with respect to an longitudinal axis of the vehicle body so that a narrowing passage is provided wherein the cross-sectional area of the flow channel is narrowed along the air flow and a widening passage of the cross-sectional area of the flow channel is widened along the air flow. Both passages are formed adjacent to each other. 
     The present invention provides the air-intake duct that has a vertically divided structure including an upper half member and a lower half member wherein the partitions are formed integrally with the upper half member and the lower half member, respectively. 
     The present invention provides the air intake duct with a cross section of substantially a laterally elongated square shape extending in the direction of the width of the vehicle when viewed from the front. A plurality of partitions are formed in the direction of the width of the vehicle. 
     In the present invention, the air-intake duct for introducing outside air disposed at the inlet port of the cleaner case includes an element for cleaning air integrated therein. The partitions for partitioning the interior of the duct are inclined with respect to the longitudinal axis of the vehicle body so that the narrowing passage provides a cross-sectional area of the flow channel that is narrowed along the air flow and the widening passage with the cross-sectional area of the flow channel being widened along the air flow. Both passages are formed adjacent to each other. 
     Consequently, the air-intake duct can be downsized, so that flexibility in designing peripheral components is increased and, simultaneously, air containing little water can be delivered to the air cleaner. 
     In addition, the air cleaner in combination with the air-intake duct constitutes a structure that can supply cleaner air to the engine. 
     In the present invention, the air-intake duct provides the vertically divided structure including the upper half member and the lower half member, and the partitions to be formed integrally with the upper half member and the lower half member, respectively. 
     Owing to the vertically divided structure, the assembly for manufacture and disassembly can be easily performed. Also, the partitions are integrally formed respectively with the upper half and the lower half and are capable of being divided into the upper and lower portions. 
     In addition, the air flow channel may be of a simple structure having no movable portion. 
     In the present invention, the air-intake duct has a cross section of substantially a laterally elongated square shape that extends in the direction of the width of the vehicle when viewed from the front. A plurality of partitions are provided in the direction of the width of the vehicle. 
     With the provision of the plurality of partitions, the air-intake duct can generate an eddy current efficiently on the side of outlet port of the air-intake duct, and can separate water from the intake air. 
     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 a two-wheel vehicle illustrating the structure of the air cleaner according to the present invention; 
         FIG. 2  is a drawing illustrating a principal portion of  FIG. 1  when viewed from the front; 
         FIG. 3  is a side view showing a positional relation between a front wheel and the air cleaner; 
         FIG. 4  is a side view showing the structure of the air cleaner according to the present invention; 
         FIG. 5  is a perspective view of an air-intake duct according to the present invention; 
         FIG. 6  is an action drawing showing an air flow of a lower half member of the air-intake duct; and 
         FIG. 7  is an explanatory drawing illustrating a basic structure of the background art. 
     
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
     Referring now to the attached drawings, a best mode for carrying out the invention will be described.  FIG. 1  is a side view of a two-wheel vehicle illustrating the structure of the air cleaner according to the present invention. A motorcycle  10  includes a main frame  11 , front forks  13  and a handle  14  both attached to a steering shaft that is rotatably supported by a head pipe  12 , which is provided at the front end of the main frame  11 . A front wheel  15  is attached to the lower end of the front fork  13 . An engine  16  attached below the main frame  11  with a speed changer  17  being provided integrally with the rear portion of the engine  16 . A swing arm  18  is attached to the rear portion of the main frame  11  with a rear wheel  19  attached to the rear end of the swing arm  18 . A fuel tank  21  is attached on the main frame  11  with a seat  22  attached behind the fuel tank  21 . A fellow passenger&#39;s seat  23  is attached behind the seat  22 . 
     An air cleaner  30  is disposed behind the head pipe  12  and the handle  14  and above the engine  16 . 
     The air cleaner  30  is provided with an air-intake duct  50  for taking in outside air at the lower front thereof. 
     A front fender  24  is provided for covering the front wheel  15  with an upper cowl  25  positioned adjacent thereto. An exhaust pipe  26  extends rearwardly from the engine  16  with a muffler  27  being connected to the exhaust pipe  26 . 
       FIG. 2  illustrates a principal portion of  FIG. 1  when viewed from the front. The air-intake duct  50  is disposed immediately above and behind the upper portion  81  of the front wheel  15  that is disposed between the front forks  13 ,  13 . A central partition  55  is provided together with partitions  56 ,  57 ,  58 , and  59 . 
       FIG. 3  is a side view showing a positional relationship between the front wheel and the air cleaner. In the air-intake duct  50 , an inlet port  82  at the extremity is located in the vicinity of the front wheel  15  located below the front fender  24 , and is connected to a radiator  87 . 
     With this positional relation, when the motorcycle  10  is traveling in a puddle or the like, the front wheel  15  splashes water from the ground  83 , as indicated by an arrow A upon contact with the ground  83 . Thus, part of the splashed water tends to enter the air cleaner  30  side through the inlet port  82  of the air-intake duct  50 . 
     Therefore, the air cleaner  30  is provided with the center partition  55  and the partitions  56 ,  57 ,  58 ,  59  in the air-intake duct  50  in order to separate water (See  FIG. 5 ). In addition, the air cleaner  30  is further provided with a water sump  85  on the lower half member  53  of the air-intake duct  50 , so that water can further be separated from intake air. 
       FIG. 4  is a side view showing the structure of the air cleaner according to the present invention. The air cleaner  30  is a structure including a cylindrical element  31 ; an air guide member  36  including a guide tube  34  formed to have a diameter d 2  smaller than the inner diameter d 1  defined between inner walls  33 ,  33  of the element  31  so as to be inserted from one end  32  of the element  31  and flange members  35 ,  35  provided on the guide tube  34  for being abutted against one end surface of the element  31 . A cleaner case  37  is provided for storing the element  31  and the air guide member  36 . A cleaner case connecting member  39  is provided on the lower side of the cleaner case  37  and below the air guide member  36  with the air-intake duct  50  being provided obliquely on the lower side of the cleaner case connecting member  39 . 
     When the air-intake duct  50  with an axis inclined with respect to the axis of the element  31  is provided on the cleaner case  37 , an inlet port  38  of the guide tube defines an inclined surface inclined in the same direction as the air-intake duct  50 . 
     An upper lid  41  of the element is provided together with a lower lid  42  of the element and an upper lid  43  of the cleaner case  37 . An element holding member  44 , is provided together with a rubber member  45  and an air-discharge duct  46 . 
     The air-intake duct  50  includes a structure that is connected to the cleaner case connecting member  39  by means of joint members  51 ,  51  and includes the upper half member  52  and the lower half member  53  so as to be divided into upper and lower halves along the vertically partitioning line  61 . In addition, a round bottom inclined portion  68  and an inclined portion  69  are provided in the longitudinal direction of the vehicle body from the left to the right in  FIG. 4 . 
     The air-intake duct  50  is provided with the water sump  85  for storing water entering from outside and a water drainage plug  86  at the midsection of the inclined portion  68 . 
     Air containing water enters through the inlet port of the air-inlet duct  50  as indicated by an arrow B, where the water content is separated therefrom and stored into the water sump  85 . Thereafter, the air enters through the inlet port  38  of the guide tube of an air guide member  36  into an dirty side in the interior of the element  31 , passes through a clean side thereof, and then enters the engine side from the air-discharge duct. 
     In the present invention, since an improvement of the structure of the air-intake duct  50  is an important point, the air-intake duct  50  will be described in detail below. 
       FIG. 5  is a perspective view of the air-intake duct according to the present invention. The air-intake duct  50  provides a structure including the joint members  51  with respect to the cleaner case connecting member  39  (see  FIG. 2 ). The upper half member  52  includes an angled roof with the lower half member  53 . Upper and lower combining members  54  (represents that there are plurality of members) are provided for the upper half member  52  and the lower half member  53  with the central partition  55  and the partitions  56 ,  57  being positioned in the vicinity of the central partitioning  55 . The partitions  58 ,  59  are positioned on both ends thereof with the vertically partitioning lines  61 , which correspond to joint portions between the upper halves and the lower halves of the partitions  55 ,  56 ,  57 ,  58 ,  59  (which are formed integrally with the upper half member  52  and the lower half member  53  of the air-intake duct  50 ). Narrowing passages  62 ,  63  are provided wherein the cross-sectional areas of the flow channels are narrowed along an air flow (arrow C). Note, the cross-sectional area is smaller on the outlet side than the inlet side (see  FIG. 6 ). Widening passages  64 ,  65  are provided wherein the cross-sectional areas of the flow channels are widened along the air flow (arrow C). Note, the cross-sectional area is wider on the outlet side than the inlet side (see  FIG. 6 ). The narrowing passages  62 ,  63  and the widening passages  64 ,  65  are surrounded by the partitions  55 ,  56 ,  57 ,  58 ,  59 , and passages  66 ,  67  wherein the cross-sectional areas of the flow channels are constant. 
     The narrowing passages  62 ,  63  and the widening passages  64 ,  65  are formed so as to be adjacent to each other and are inclined with respect to the longitudinal axis of the vehicle body. The round bottom  68  inclined portion is inclined forwardly of the vehicle body formed on the forward bottom of the air-intake duct  50 , and the inclined portion  69  extends rearwardly of the round bottom inclined portion  68  and is inclined forwardly of the vehicle body. The plurality of water sumps  85  project downwardly and are disposed on the front side of the round bottom inclined portion. The water drainage plug  86  (see  FIG. 4 ) for discharging water is provided at the lower end of the water sump  85 . 
       FIG. 6  is an action drawing showing the air flow of the lower half member of the air-intake duct, and the lower half member  53  of the air-intake duct  50  when viewed from above. The center partition  55  is disposed at the center with the partitions  56 ,  57  being disposed symmetrically in the vicinity of the center partition  55 . The partitions  58 ,  59  are disposed at the positions near both ends with the narrowing passages  62 ,  63  and the widening passages  64 ,  65  being surrounded by these partitions  55 ,  56 ,  57 ,  58 ,  59 . The water sump  85  is disposed below the left and right partitions  56 ,  57  at a position sifted in the fore-and-aft direction of the vehicle body. 
     Air enters from the front of the vehicle body as indicated by an arrow D, and is separated into two routes; one is flowing, at the inlet port of the cleaner case connecting member  39  (not shown), from the outlet ports  71 ,  72  of the widening passages  64 ,  65  to the outlet ports  73 ,  74  of the narrowing passages  62 ,  63  like an eddy current as indicated by arrows E. The second route flows straight forward as shown at the outlet ports of the passages  66 ,  67 . Water entered into the narrowing passages is attached to the partitions  56 ,  57 , so that it can be separated from the air. Water attaches to the partitions  56 ,  57  and runs along the inclined portion  69  (see  FIG. 5 ) and the round bottom inclined portion of the lower half member  53  of the air-intake duct  50 , and is stored in the water sump  85 , from which it is discharged to the outside by means of the water drainage plug  86  (see  FIG. 4 ). 
     The arrows E show eddy currents flowing from the outlet ports  71 ,  72  wherein the cross-sectional areas of the flow channels are large relative to the outlet ports  73 ,  74  wherein the cross-sectional areas of the flow channels are small. This is based on a phenomenon in which the air pressure is high at the outlet ports  71 ,  72  wherein the cross-sectional areas of the flow channels are large and, in contrast, is low at the outlet ports  73 ,  74  wherein the cross-sectional areas of the flow-channels are small. Thus, the air flows like an eddy current that is generated from the high-pressure side to the low-pressure side. 
     As a consequence, water that entered into the widening passage  64  and the narrowing passage  62  is stored in the water sump  85  (see  FIG. 4 ) on the inlet port side of the air-intake duct  50  inclined toward the front. 
     The air-intake duct has an advantage not only in that a large space is not necessary, but also in that air having little water can be delivered to the air cleaner without impairing a smooth air flow. 
     The material of the air-intake duct of the present invention may be resin or metal. However, when considering its shape, light weight requirement, and cost reduction, resin is preferable. 
     The internal structure of the air-intake duct may be of any type as long as the narrowing passage and the widening passage are disposed adjacent to each other, and the number thereof is not limited. Although the air-intake duct of the present application is disposed only one at the upper rear position of the front wheel, there may be a plurality of air-intake ducts disposed separately in the direction of the width of the vehicle body or in the direction of the fore-and-aft direction of the vehicle body. 
     In addition, although the shape of the cross section of the air-intake duct in the present application is substantially a laterally elongated square, it may be a laterally enlongated square, or a circle. 
     The air cleaner structure of the present invention is suitable for a two-wheel 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.