Patent Abstract:
A compact air cleaner for a motorcycle engine has its intake duct directed in a widthwise direction of the motorcycle. The air cleaner includes an air cleaner case, an air cleaner element and a case cover. The air cleaner element partitions an inner portion of the air cleaner case and case cover into a clean room and a dirty room. The air cleaner element extends in the motorcycle&#39;s travel direction. An intake port communicates with the dirty room and opens to a space surrounded by a rear face of the clean room, a front portion of a rear fender and a bottom portion of a seat.

Full Description:
BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     The present invention relates to a structure of an air cleaner of a motorcycle. 
     2. Description of the Background Art 
     Air cleaners for motorcycle engines are well known. One air cleaner structure for a motorcycle is shown in Japanese Utility Model Registration No. 2537385. In the shown air cleaner, a clean room and a dirty room are arranged in a widthwise direction of a vehicle with a flat plate air cleaner element disposed therebetween. Air is sucked from a rearward direction of a motorcycle via a rearwardly extending intake duct. The air passes into the dirty room, through the air cleaner element, into the clean room, then to the engine. 
     When an air cleaner is constructed, as in the above-described conventional example, a capacity/size of the dirty room and a length/size of the intake duct all add to the size of the air cleaner in the lengthwise direction of the motorcycle. In order to have an air cleaner which functions sufficiently, a side face of the air cleaner, including the dirty room and the intake duct, is extended in length, thereby making the air cleaner bulky in construction. 
     SUMMARY OF THE INVENTION 
     It is an object of the present invention to provide an air cleaner of compact construction. Particularly, it is an object of the present invention to provide an air cleaner which has a compact construction in a lengthwise direction of the motorcycle. 
     It is a further object of the present invention to provide an air cleaner with improved ventilation efficiency. 
     It is an even further object of the present invention to provide an air cleaner having an intake duct which is less susceptible to invading water or dust. 
     These and other objects of the present invention are achieved by providing an air cleaner for an engine of a vehicle, said air cleaner comprising: an air intake port extending in a first direction to accept outside air; an air flow path connected to said air intake port for redirecting a flow of the outside air approximately 180 degrees and yielding redirected air into a dirty air chamber; an air cleaner element adjoining said dirty air chamber for filtering the redirected air and for producing cleaned air; and a clean air chamber adjoining said air cleaner element for accepting the cleaned air and for directing the cleaned air toward the engine. 
     These and other objects of the present invention are achieved by providing a motorcycle comprising: a frame; an engine attached to said frame; a seat attached to said frame; a rear wheel fender attached to said frame; an air intake port extending in a first direction to accept outside air at a first location; an air flow path connected to said air intake port for redirecting a flow of the outside air approximately 180 degrees and yielding redirected air into a dirty air chamber; an air cleaner element adjoining said dirty air chamber for filtering the redirected air and for producing cleaned air; a clean air chamber adjoining said air cleaner element for accepting the cleaned air; and an outlet port connected to said clean air chamber for passing the cleaned air toward said engine. 
     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 cross sectional view of an air cleaner, according to the present invention; 
     FIG. 2 is a side view of a motorcycle including the air cleaner of FIG. 1; 
     FIG. 3 is a perspective view of the air cleaner partially disassembled; 
     FIG. 4 is a side view of the air cleaner when assembled; 
     FIG. 5 is a cross sectional view taken along line  5 — 5  of FIG. 4; 
     FIG. 6 is a cross sectional view taken along line  6 — 6  of FIG. 4; and 
     FIG. 7 is a side view showing the air cleaner case with a cover removed. 
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
     With reference to FIG. 2, structures of a motorcycle, including an air cleaner  10  in accordance with the present invention, will be described. A front end  1  of the motorcycle includes a front fork  2  and handlebars  5 . An upper portion of the front fork  2  is attached to a head pipe  3 . The head pipe  3  is attached to a vehicle body frame  5 . 
     The vehicle body frame  5  supports a fuel tank  6  and a seat  7  on an upper side. The vehicle body frame  5  supports an engine  8  on a lower side. The engine  8  is a water-cooled type, cooled by a radiator  9 . The engine  8  intakes air from the air cleaner  10  on the lower side of the seat  7 . The engine accepts the air via a carburetor  11  and exhausts gas from an exhaust port via an exhaust pipe  12 . 
     A rear swing arm  14  is supported by a pivot portion  15  attached to a portion of the vehicle body frame  5  on the rear side of a crank case  13  of the engine  8 . The swing arm can swing in the up and down direction. A rear shock absorber  16  is installed between the rear swing arm  14  and the vehicle body frame  5 . 
     A rear wheel  17  is supported by a rear end portion of the rear swing arm  14 . The rear wheel  17  is driven by a side sprocket  18  connected to a chain  19  connected to a drive side sprocket  20  of the crank case  13 . The rear wheel  17  can move up and down by swinging the rear swing arm  14 . 
     A rear portion of the air cleaner  10  is arranged adjacent the rear wheel  17 . The air cleaner  10  is arranged such that when the rear wheel  17  is moved to an uppermost position (as shown by the dotted line in FIG.  2 ), the air cleaner  10  does not contact or interfere with the rear wheel  17 , but overlaps a side thereof. Thereby, even when the rear wheel  17  is arranged to be proximate to the engine  8 , a capacity of the air cleaner  10  can be sufficiently large. 
     Further, as discussed hereinafter, an air cleaner element  41  in conformity with a shape of a side face of the air cleaner  10  is provided inside the air cleaner  10 . By having the air cleaner element  41  in conformity with the shape of the side face, the air cleaner element can have a large surface area. 
     The motorcycle also includes a step bracket  21 , a chain protector  22 , a rear stay  23 , a seat rail  24  and a rear fender  25 . The vehicle body frame  5  is formed in a loop shape in side view. 
     The vehicle body frame  5  includes a head pipe  30 , a main pipe  31 , a center pipe, a pivot frame  33 , lower pipes  34 , a down pipe  35  and a reinforcement pipe  36 . Of these pipes and frames, single ones of the main pipe  31 , the center pipe, the pivot frame  33  and the down pipe  35  are arranged along the center of the vehicle body to thereby constitute a backbone type frame. Further, left and right pairs of the lower pipes  34 , the rear stays  23  and the seat rails  24  are respectively installed. 
     The head pipe  30  is a hollow member integrated with the head pipe  3  and cast by using a pertinent metal material of an aluminum alloy or the like. The main pipe  31  is a member constituting a straight shape in a square pipe shape constructed of a suitable metal material. A front end portion of the main pipe  31  is coupled to the head pipe  30  by welding, a rear end portion thereof is cut obliquely and is brought into contact with and welded to an upper end portion of the center pipe which is similarly cut obliquely. 
     The center pipe is a square pipe member constituting a straight shape constructed of a suitable metal material of an aluminum alloy or the like. The center pipe is provided with a section similar to that of the main pipe  31 . A rear face side of the center pipe, at a vicinity of a joint portion, joins with the main pipe  31 , and is welded with a bracket having portions for attachment to the seat rails  24  and the rear shock absorber  16 . A lower end portion of the center pipe is brought into contact with and welded to an upper end portion of the pivot frame  33 . 
     The pivot frame  33  is fabricated by casting an aluminum alloy and constitutes a substantially U-shaped configuration, opening to the front side of the motorcycle. An intermediary portion of the pivot frame  33  is provided with a pivot portion  15 . A lower end portion of the pivot frame  33  is provided with lower pipe joint portions  38  to which rear end portions of the lower pipes  34  are fitted and welded. 
     The lower pipes  34  are arranged in the forward and rearward direction on the lower side of the engine  8 . Front end portions of the lower pipes  34  are bent upwardly and welded to a lower end portion of the down pipe  35  via a joint piece (illustration is omitted). The joint piece is a casting of an aluminum alloy or the like. 
     Next, an explanation will be given of a detailed structure of the air cleaner, in accordance with the present invention. As shown in FIG. 3, the air cleaner  10  includes an air cleaner case  40  which is opened to one side (e.g. left side) of the vehicle body. A case cover  42  is provided to close the one side of the air cleaner case  40 . 
     The air cleaner case  40  and case cover  42  define an inner space. An air cleaner element  41  partitions the inner space formed by the air cleaner case  40  and a case cover  42 . As shown in FIG. 5, the inside of the air cleaner case  40  is partitioned into a clean air chamber, or clean room  43 , and a dirty air chamber, or dirty room  44 , in the vehicle width direction, by the air cleaner element  41 . As illustrated in FIGS. 1 and 3, the air cleaner element  41  is a generally planar member which extends approximately vertically and in the forward and rearward direction, or travel direction of the vehicle. 
     As illustrated in FIG. 3, the clean room  43  extends to the other side of the vehicle body by passing over the center of the vehicle body (e.g. left side to right side of vehicle body). The clean room  43  passes over the vehicle body in front of the rear fender  25 . A front portion of the clean room  43  is connected with a connecting tube  45  to supply clean air to the carburetor  11  of the engine  8 . 
     The dirty room  44  extends rearward along a side face of the rear fender  25 . The air cleaner case  40  and the case cover  42  are respectively provided with rearward extended portions  46   a  and  46   b . The case cover  42  is integrally formed with a rear cover portion  47  extending rearward longer than the rearward extended portion  46   b . The rear cover portion  47  covers an opening portion of the air cleaner case  40 . 
     As shown in FIGS. 1,  3 ,  6  and  7 , an intake port  50  is formed at the shoulder portion of the rearward extended portion  46   b . The intake port  50  communicates a space  51  with the dirty room  44 . The space  51  is defined by a rear face of the clean room  43 , a front portion of the rear fender  25 , and a bottom portion of the seat  7 . A notched portion  52  is formed in the air cleaning element  41  to correspond with the intake port  50  (see FIG. 3) to thereby open the intake port  50  to the dirty room  44 . 
     As shown in FIG. 4, the case cover  42  is removably attached to the side of the air cleaner  40  by coupling pieces  48  of the one touch system type. Some of the coupling pieces may also serve as hinges  49 . Further, as shown in FIG. 6, a portion of the intake port  50  is coupled to a bridge portion  53  formed at an intermediary portion thereof by the coupling piece  48 . A portion of the intake port  50  is closed by a cap  54 . 
     As shown in FIG. 1, a portion of a wall face  55  of the clean room  43  is brought into contact with the rear fender  25 . This portion of the wall face  55  includes a recess groove  56 . A projection  57  is provided on the side of the rear fender  25 . The projection  57  mates with the recess groove  56  to connect the rear fender  25  to the clean room  43 . It should be noted that the relationship between the recess groove  56  and the projection  57  may be reversed. 
     FIG. 3 illustrates a water removing rib  58  formed on the upper face of the rear fender  25 . FIG. 3 also illustrates a dust removing rib  59  formed on the upper face of the rear fender  25 . FIG. 4 illustrates a breather pipe  60  and a drain pipe  61 . 
     Next, an explanation will be given of the operation of the air cleaner, in accordance with the present invention. As shown in FIG. 1, outside air is sucked from the space  51  form between the rear face of the clean room  43 , the front portion of the rear fender  25 , and the bottom portion of the seat  7 . The outside air is sucked in along a first flow direction extending through the intake port  50 . 
     The air enters the dirty room  44  on the lower side of the intake port  50 . The air then changes its flow direction to a direction toward the center of the vehicle. Next, the air passes through the air cleaner element  41  and enters into the clean room  43 . 
     Concerning one advantage of the present invention, the intake port  50  extends in a widthwise direction of the vehicle. Therefore, the intake port  50  need not extend rearwardly, as in the background art. Since the length of the overall air cleaner, in the forwards-backwards direction (i.e. travel direction of the vehicle), is shortened by redirection of the intake port  50 , it is possible to expand the relative sizes of the clean room  43  and the dirty room  44  if desired, while preserving, or even shortening, the length of the overall air cleaner. Even if the rooms  43 ,  44  are expanded in size, a total length of the overall air cleaner in the forward and rearward direction and in an width extending to a side of the motorcycle, are reduced, resulting in making the air cleaner very compact. 
     Concerning another advantage of the present invention, as illustrated in FIGS. 1 and 3, the air cleaner element  41  is a generally planar member which can be approximately arranged in a first plane which extends in the up and down (vertical) direction and forward and rearward (travel) direction. Accordingly, the surface area of the air cleaner element  41  is enlarged, relative to the background art. Therefore, the ventilation efficiency of the air cleaner is increased. 
     Concerning yet another advantage of the present invention, outside air is sucked from the space  51  surrounded by the rear face of the clean room  43 , the front portion of the rear fender  25  and the bottom portion of the seat  7 . Accordingly, invading water or dust is reduced, relative to the background art. Invading water and dust is even further reduced by the presence of the water removing rib  58  and the dust removing rib  59 . By so locating and directing the air inlet, clogging of the air cleaner element  41  becomes less likely, and easier to prevent. 
     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.

Technology Classification (CPC): 5