Abstract:
To improve the durability of an air cleaner against water and dirt sucked in from a drain hole. An air cleaner includes an air cleaner element and a case cover. The inside of the air cleaner is partitioned into a clean room and a dirty room by an air cleaner element, and is aligned in a widthwise direction of the vehicle. The dirty room communicates with the atmosphere through an intake hole provided at an upper section, and a drain hole and a drain pipe are provided in a bottom wall section. A rib for supporting a lower end of the air cleaner element is provided above the bottom floor section, and is arranged so as to cross an extension of the axis of the drain pipe. Water and dirt that are sucked into the dirty room through the drainpipe and the drain hole by negative pressure inside the air cleaner have difficulty coming into direct contact with the air cleaner element because of the rib acting as a baffle plate.

Description:
BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     The present invention relates to an air cleaner for a motorcycle type vehicle. 
     2. Description of Related Art 
     Japanese utility model laid-open No. Sho. 60-19764 discloses a structure having a drain hole provided in a lower part of a dirty room of an air cleaner, with a rubber cap as a one-way structure covering the drain hole. With this construction, water is only discharged from the inside of the dirty room to the outside. 
     The rubber cap in the above-described related art is a one-way structure. However, since there is negative pressure inside the air cleaner, there will inevitably be air penetrating into the air cleaner from gaps in the discharge ports provided in the rubber cap. At the same time, water and dirt contained in the penetrating air will invade into the inside of the air cleaner. Therefore, there is a danger that the water and dirt will stick directly to the air cleaner element. As a result, there is a need to improve the durability of the air cleaner element, etc. against this sort of water and dirt invading into the air cleaner through the drain hole. The present invention has been conceived to satisfy this demand. 
     SUMMARY OF THE INVENTION 
     In order to solve the above described problems, the air cleaner of the present invention includes an inside of an air cleaner case which is partitioned into a clean room and a dirty room by an air cleaner element. The clean room is connected to an engine and an intake hole leading to the atmosphere is provided in an upper part of the dirty room. Furthermore, a drain hole is provided in a lower part of the dirty room and a baffle plate is provided on an extension of an axis of a passage section of the drain hole. 
     With the above-described structure, even if water and dirt invade into the inside of the dirty room from the drain hole, since a baffle plate is provided on an extension of the axis of the passage of the drain hole, the water and dirt are stopped by this baffle plate. In this way, it is difficult for the water and dirt to invade any further. As a result, the water and dirt do not become directly attached to the air cleaner element. Therefore, it is possible to improve the durability of the air cleaner element. 
     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 drawing of a drain portion of an air cleaner of the present invention along line  1 — 1  in FIG. 3; 
     FIG. 2 is an overall side elevation of a motorcycle adopting the air cleaner of the present invention; 
     FIG. 3 is a side elevation of the air cleaner of the present invention; 
     FIG. 4 is a cross sectional drawing along line  4 — 4  in FIG. 3; 
     FIG. 5 is a cross sectional drawing along line  5 — 5  in FIG. 2; and 
     FIG. 6 is a schematic drawing of a rib shown in the direction of arrow X in FIG.  1 . 
    
    
     DESCRIPTION OF THE PREFERRED EMBODIMENTS 
     Embodiments of the present invention will now be described with reference to the attached drawings. FIG. 1 is a cross sectional drawing along line  1 — 1  in FIG. 3 showing the drain structure of an air cleaner of an embodiment of the present invention; FIG. 2 is an overall side elevation of a motorcycle adopting the embodiment of the present invention; FIG. 3 is a side elevation of the air cleaner; FIG. 4 is a cross sectional drawing along line  4 — 4  in FIG. 3; FIG. 5 is a cross sectional drawing along line  5 — 5  in FIG. 2; and FIG. 6 is a schematic drawing of a rib shown in the direction of arrow X in FIG.  1 . 
     First of all, the general structure of a motorcycle adopting the embodiment of the present invention will be described with reference to FIG.  2 . Reference numeral  1  represents a front wheel, reference numeral  2  represents a front fork, reference numeral  3  represents a head pipe, reference numeral  4  represents a handle bar, reference numeral  5  represents a vehicle frame, reference numeral  6  represents a fuel tank, reference numeral  7  represents a seat, and reference numeral  8  represents an engine. engine  8  is a water cooled engine, with coolant cooled in a radiator  9 . The engine  8  has intake from an air cleaner  10  arranged underneath the seat  7  via a carburetor  11 , and exhaust from an exhaust port via an exhaust pipe  12 . 
     A rear swingarm  14  supported so as to swing on the vehicle frame  5  behind a crank case  13  has a rear cushion unit  15  attached at a center section thereof. The rear swingarm  14  supports a rear wheel  16  at a rear end section thereof. 
     The rear wheel  16  overlaps the side of an air cleaner case  10 , when viewed from the side. The rear wheel  16  does not obstruct the air cleaner case  10 , even at the position of the imaginary line in FIG. 2, when the rear wheel  16  is at its maximum upward displacement. In this way, it is possible to locate the rear wheel  16  close to the engine  8 , and to increase the capacity of the air cleaner. 
     As shown in FIGS. 3 and 4, the air cleaner  10  is comprised of an air cleaner case  20  opening out to one side of the vehicle (the left side of the vehicle). and an air cleaner element  21  and case cover  22  partitioning the inside of the air cleaner case  21 . As is clear from FIG. 4, the inside of the air cleaner case  20  is partitioned in a widthwise direction of the vehicle into a clean room  23  and a dirty room  24  by the thin plate air cleaner element  21  extending in a longitudinal direction. 
     The clean room  23  has substantially an L shape viewed in plan. A front side section of the clean room  23  extends from one side (the left side of the vehicle) along the leading edge of the rear wheel  16  to the other side (the right side of the vehicle). One end of a connecting tube  25  is connected to a front part of the section extending to the other side. The other end of the connecting tube  25  is connected to a carburetor  11 . Clean air is supplied from the air cleaner  10  to the carburetor  11 . 
     A rear part of the clean room  23  extends along the side of the rear wheel  16 , when viewed in plan, and the dirty room  24  also extends along one side of the vehicle, substantially parallel to a rear section of the clean room  23 . 
     By providing the clean room  23  and the dirty room  24  extending a long way in a longitudinal and vertical direction of the vehicle, the clean room  23  and the dirty room  24  are respectively sufficiently increased in capacity. At the same time, the air cleaner  10  can be made compact without any lateral overhang. 
     Rear extension sections  26   a  and  26   b  extending to the side of the rear wheel  16 , when viewed in plan, and respectively corresponding to rear sections of the clean room  23  and the dirty room  24  are provided in the air cleaner case  20  and the case cover  22 , respectively. Furthermore, in addition to the main body sections, a, rear cover  27  extending further rearward than the rear extension section  25   b  is formed integrally with the case cover  22 . 
     As is clearly shown in FIG. 5, an upper part of the rear extension section  26   b , being a rear part of the case cover  22 , extends upwards further than the rear extension section  26   a  that is a rear part of the air cleaner case  20 . Furthermore, the upper part of the rear extension section  26   b  runs along an outer side of the seat rail  18  to the seat  7 , and forms a space  28  leading to the atmosphere between the seat  7  and the rear fender  17 . 
     A lateral opening section  29  opening to the side is formed in a vertical wall section for partitioning the dirty room  24  and the space  28  at an upper section of the rear extension section  26   a  of the air cleaner case  20 . The space  28  and a rear upper chamber  24   a  of the dirty room  24  are connected together by the lateral opening section  29 . The lateral opening section  29  replaces a rearwardly extending duct in the related art, which can be omitted. 
     A rear shoulder of the air cleaner element  21  is cut away so that it does not overlap the lateral opening  29 . Furthermore, the air cleaner element  21  has filter surfaces arranged substantially parallel to the vertical and longitudinal directions of the vehicle. This means that it is easy to have a structure in which the surface area of the air cleaner element  21  is large and ventilation efficiency is increased. 
     An upper wall section  30  of the dirty room, projecting towards the inside, is integrally formed at an inner side of the case cover  22 , with a projecting end section  33  of the upper wall section  29  supporting an upper end section of the air cleaner element  21 . An intake hole  32 , which opens upwards, is formed in the upper wall  30  in order to connect the space  28  with the dirty room  24 , through the rear upper chamber  24   a  and the lateral opening section  29 . 
     A bottom wall section  33 , projecting from an inner side of a lower end of the case cover  22  towards the inside, is integrally formed lower than the upper wall section  30  of the dirty room. A rib  34  provided just above the bottom wall section  33  supports a lower end of the air cleaner element  21 . 
     Furthermore, as will be clearly understood from FIG. 1, a drain hole  35  is provided in a front section of the bottom wall section  33 . The drain bole  35  opens outwardly downwardly. Furthermore, the drain hole  35  connects to a drain pipe  36  formed projecting integrally downwardly from a lower section of the bottom wall section  33 . A drain tube  37  is connected to a lower end of the drain pipe  36  using a clip  38 . 
     The drain tube  37  is suitable as a passage section of the drain hole  35 , and is formed from a suitable material having flexibility, such as rubber. A lower end of the drain tube  37  is formed into an opening and closing slit  37   a . The slit  37   a  is normally closed, and only opens when water, etc. is discharged from the inside of the dirty room  24  to the outside, in the same manner any of the well known one-way valves. 
     The axis L of the drain pipe  36  passes through the center of the drain hole  35  and the slit  37   a , and the rib  34  is provided on the inside of the dirty room  24  crossing an upward extension of the axis L. The rib  34  has a tapered cross section, becoming thinner towards its tip, and constitutes a member functioning as a baffle plate of the present invention. 
     Also, as will be clear from FIG. 6, schematically showing the rib  34  from the direction of arrow X in FIG. 1, slits  34   a  are cut into the rib  34  at suitable intervals along its length. The drain hole  35  overlaps the rib  34  in the direction of the axis L (FIG.  1 ), and the slits  34   a  are arranged at positions away from the axis L so that they do not overlap the drain hole  35 . 
     On the other hand, as will be clearly understood from FIG.  1  and FIG. 5, an upper wall section  40 , projecting outwardly, is also provided in the air cleaner case  20 . A projecting end  41  of the upper wall section  40  engages with the projecting end  31  so that the upper end of the air cleaner element  21  is sandwiched between the projecting end  31  and the upper wall  40 . 
     A lower wall section  42  of the air cleaner case  20  is provided projecting outwards below the upper wall  40 . A projecting end of the lower wall section  33  is fitted into a grooved section provided in a projecting end  43  of the lower wall section  42 . Furthermore, a rib  44  provided just above this grooved section sandwiches a lower end of the air cleaner element  21  together with the rib  43 . 
     The operation of the embodiment of the present invention will now be described. As shown in FIG. 5, outside air enters into the inside of the rear upper chamber  24   a  through the space  28  and the lateral opening section  29 , enters into the dirty room  24  from the intake hole  32 . Inside the dirty room  24 , the flow is changed toward the center of the vehicle so that air is cleaned by the air cleaner element  21  and enters the inside of the clean room  23 . After that, air in a front section of the clean room  23  flows to the other side and is supplied from the connecting tube  25  to the carburetor  11 . 
     At this time, the majority of moisture penetrating into the dirty room  24  together with the outside air through the lateral opening section  29  and the intake hole  32  is suitably subjected to vapor-liquid separation because the air flow winds in a labyrinthine shape, the moisture component flows downwards via the rib  34  and the slits  34   a  into the dirty room  24 , and is discharged to the outside from the drain hole  35  through the drain pipe  36 . 
     The inside of the air cleaner  10  is repeatedly alternating between positive pressure and negative pressure due to intake pulsation of the engine  8  connected via the connecting tube  25 . This means that when the air cleaner is at negative pressure, external air is sucked in to a certain extent even if the slit  37   a  of the drain tube  37  is closed. In such a case, water and dirt as well as air are sucked in through the slit  37   a , and sometimes penetrate inside the dirty room  24  from the drain pipe  36  through the drain hole  35 . 
     However, a large part of the water and dirt that are sucked in in this way run along the axis L of the drain pipe  36  and penetrate into the dirty room  24 , but because the rib  34  is positioned in an extension of this axis L, they collide with this rib  34 . 
     As a result, the rib becomes a type of baffle plate with respect to the water and dirt. It is therefore difficult for the water and dirt to pass the rib  34  and penetrate to the other side. This means that the amount of water and dirt that stick directly to the air cleaner element  21  can be made extremely small, resulting in improved durability of the air cleaner element  21 . 
     Accordingly, this structure is well suited to vehicles that are prone to the invasion of water and dirt, such as off-road motorcycles and buggy type vehicles. However, it goes without saying that it can also be applied to on-road motorcycles and other vehicles. 
     Furthermore, since the rib  34 , integral with the case cover  22 , and supporting the air cleaner element  21 , is used as a baffle plate, there is no longer any need to provide a dedicated baffle plate. This makes it possible to simplify the structure and reduce the manufacturing cost. However, it is still possible to provide a baffle plate independently of the rib  34 , and to make the baffle plate separate from the case cover  22 . 
     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.