Abstract:
A mounting structure of an exhaust pipe system in a vehicle capable of making a magnitude of a moment acting on the exhaust pipe system as small as possible by means of a simple constitution. In a mounting structure of an exhaust pipe system in a vehicle the exhaust pipe system is connected to an engine loaded onto the vehicle and for guiding exhaust gas discharged from the engine to the ambient air, on a vehicle body frame constituting the vehicle, wherein the exhaust pipe system is constituted so as to be connected to the vehicle body frame in a position substantially upwardly from a position G of the center of gravity of the exhaust pipe system.

Description:
BACKGROUND OF THE INVENTION  
         [0001]    1. Field of the Invention  
           [0002]    The present invention relates to a mounting structure of an exhaust pipe system for a vehicle.  
           [0003]    2. Description of Background Art  
           [0004]    Conventionally, for example, in a vehicle such as a saddle-type vehicle, as disclosed in Japanese Examined Utility Model Publication H1-33778, the vehicle is provided with an engine loaded onto a vehicle body frame and an exhaust pipe system for emitting exhaust gas discharged from the engine to the atmosphere. The exhaust pipe system extends rearwardly along a side portion of a vehicle body from the engine, and is suspended to a rearward side portion of the vehicle body frame.  
           [0005]    A problem exists with the mounting structure of a conventional exhaust pipe system in that a moment is generated around a suspended position of the exhaust pipe system due to vibration or the like which occurs during the operation of the vehicle.  
           [0006]    When a moment like this is generated, in particular, since a muffler constituting the exhaust system is a heavy article, a large load operates on a connecting portion of the exhaust pipe system with an engine.  
           [0007]    Thus, in the prior art described above, in order to decrease the load operating on the connecting portion, such a measure is taken such that a shock absorbing body formed out of an elastic material, such as rubber, is mounted on the connecting portion described above.  
           [0008]    However, in such a method as coping with the problem described above, not only the shock absorbing body stated above, but also various components are necessitated for mounting the shock absorbing body. Thereby, the number of parts of the exhaust pipe system are increased, so that weight of the vehicle is increased or a sharp rise in cost occurs.  
         SUMMARY AND OBJECTS OF THE INVENTION  
         [0009]    The present invention overcomes the above conventional problems. It is an object of the invention is to provide a mounting structure of an exhaust pipe system in a vehicle that is capable of making the magnitude of a moment operating on the exhaust system as small as possible by means of a simple constitution.  
           [0010]    To achieve the object described above, in a first aspect of the invention, a mounting structure for an exhaust pipe system in a vehicle, in which the exhaust pipe system is connected to an engine loaded onto the vehicle and for guiding exhaust gas discharged from the engine to outside air is mounted on a vehicle body frame constituting the vehicle. The exhaust pipe system is connected to the vehicle body frame in a position substantially upwardly from a position of the center of gravity of the exhaust pipe system.  
           [0011]    In a second aspect of the invention, a mounting structure of an exhaust pipe system in a vehicle according to the first aspect includes the exhaust pipe system having an exhaust pipe connected to the engine and a muffler integrally formed with the exhaust pipe. The exhaust pipe system is connected to the vehicle body frame in the position substantially upwardly from the position of the center of gravity of the exhaust pipe system including the exhaust pipe and the muffler.  
           [0012]    In a third aspect of the invention, a mounting structure of an exhaust pipe system in a vehicle according the first aspect includes the exhaust pipe system having an exhaust pipe connected to the engine and a muffler connected to the exhaust pipe, and the muffler is connected to the vehicle body frame in the position substantially upwardly from the position of the center of gravity of the muffler.  
           [0013]    In a fourth aspect of the invention, a mounting structure of an exhaust pipe system in a vehicle according to the first to third aspects includes the exhaust pipe system connected to the vehicle body frame, in such a manner that a bracket is provided at a position mounted with the exhaust pipe system on the vehicle body frame. A stay is provided on the vehicle body frame that is connected and opposed to the bracket from a side portion of the vehicle body frame. The bracket is connected with the stay via a shock absorbing member. The shock absorbing member includes a shock absorbing disk interposed between the bracket and the stay and a shock absorbing cylinder pierced through the bracket to be brought into contact with the shock absorbing disk provided with an annular outward flange to be brought into contact with the bracket in a side opposed to the stay; and the shock absorbing member. The stay and the bracket are Jointly fastened by means of a fastening member provided by piercing through the shock absorbing disk and shock absorbing cylinder.  
           [0014]    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. 
       
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0015]    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:  
         [0016]    [0016]FIG. 1 shows a schematic side elevational view illustrating a saddle-type vehicle of an embodiment of the present invention;  
         [0017]    [0017]FIG. 2 shows a schematic side elevational view illustrating a generating state of a load when vibrating in a mounting structure of a conventional exhaust pipe system;  
         [0018]    [0018]FIG. 3 shows a schematic side elevational view illustrating a generating state of a load when vibrating in an embodiment of the present invention; and  
         [0019]    [0019]FIG. 4 shows an exploded plan view for explaining a suspension structure of a muffler in illustrating an embodiment of the present invention. 
     
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS  
       [0020]    Hereinafter, an embodiment of the present invention will be described with reference to the drawings. In FIG. 1, a saddle-type vehicle  1  is a vehicle applied to the present embodiment.  
         [0021]    The saddle-type vehicle  1  is provided with a pair of a left and right main pipes  2  constituting an upper portion of a vehicle body portion. A pair of a left and right under pipes  3  arranged along downwardly from the main pipes  2  and connected to the main pipes  2  in a forward side. A rear fork  4  is vertically and rockably mounted on the under pipes  3  on a rearward side thereof. An engine  5  is arranged at a spatial portion formed by the main pipes  2  and the under pipes  3 . Further, fixed to the under pipe  3 , a pair of a left and right front wheels  6  are vertically and movably mounted on left and right front portions of the main pipes  2  and the under pipes  3 . A pair of rear wheels  7  are mounted on left and right sides of the rear fork  4 .  
         [0022]    Further, a steering handlebar  8  provides for the steering of the front wheels  6  at a front portion of the main pipes  2 . A fuel tank  9  is provided rearwardly of the steering handlebar  8 .  
         [0023]    In addition, a seat  11  is supported by means of seat pipes  10  extending and being provided towards the rearward of the main pipes  2  to the rear of the fuel tank  9 . An air cleaner  12  is provided for cleaning up combustion air supplied to the engine  5  downward of the seat  11 .  
         [0024]    Further, an exhausted pipe system is provided for emitting combustion gas to outside air, and for restraining exhaust noise from the engine  5 . The exhausted pipe system includes an exhaust pipe  13  connected to the engine  5  and a muffler  14  continuously provided at the end portion downstream of the exhaust pipe  13 .  
         [0025]    On the other hand, the rear fork  4  is provided vertically and rockably supported by means of a bearing  16  mounted on a pivot plate  15  at a rear portion of the under pipes  3 .  
         [0026]    Further, in the present embodiment, the muffler  14  is connected in the tip portion thereof at a rear end portion of the exhaust pipe  13  via a coupling member  30 .  
         [0027]    Further, the muffler  14  is provided with a bracket  17  in a position upwardly from a position G of the center of gravity thereof A stay  18  (refer to FIG. 4) is provided in a rearward side portion of the seat pipe  10 , as the bracket  17  is connected to the stay  18 , so that the muffler  14  is suspended from the seat pipe  10 .  
         [0028]    In describing in further detail, the bracket  17 , as illustrated in FIG. 4, is formed substantially in a shape of U and, as described above, is integrally mounted on the muffler  14  in a position upwardly from the position G of the center of gravity thereof by means of welding or the like.  
         [0029]    Further, a collar  19  is integrally mounted on the bracket  17  along a direction that is across at right angle with an axial direction of the muffler  14 , the collar  19  is mounted with a shock absorbing member  20  interposed between the stay  18  and the bracket  17 .  
         [0030]    The shock absorbing member  20  includes an annular shock absorbing disk  21  having an outer diameter larger than an outer diameter of the collar  19  and interposed between the collar  19  and the stay  18 , and a shock absorbing cylinder  22  which is pierced through the collar  19  and is brought into contact with the shock absorbing disk  21 , and is provided with and annular outward flange portion  22   a  placed in contact with the collar  19  on the side opposed to the stay  18 .  
         [0031]    Further, the shock absorbing disk  21  is arranged between the stay  18  and the collar  19 , the shock absorbing cylinder  22  is inserted into the collar  19 , the outward flange  22   a  of the shock absorbing cylinder  22  is brought into contact with the end face of the collar  19 , a fastening member composed of a bolt  23  and a nut  24  is pierced through the stay  18 , the shock absorbing disk  21 , and shock absorbing cylinder  22 , so that the muffler  14  is connected to the seat pipe  10  by jointly fastening the elements.  
         [0032]    In the exhaust pipe system mounted in this manner, in association with the operation of the saddle-type vehicle  1 , vibration is generated.  
         [0033]    However, as described above, since the muffler  14  is installed on the seat pipe  10  in a position upwardly from the position G of the center of gravity thereof, as illustrated by an arrow in FIG. 3, a load which acts on the muffler  14  directly acts beneath with respect to the fastening member  23 ,  24 .  
         [0034]    As a result, generation of a moment around the fastening member  23 ,  24  is restrained.  
         [0035]    Accordingly, excessive force is prevented from acting on a connection portion X of the exhaust pipe  13  with the engine  5 , and a connection portion Y of the exhaust pipe  13  with the muffler  14 .  
         [0036]    Here, in comparison with the conventional art, in the conventional method, as illustrated in FIG. 2, caused by a displacement distance L between a position Z of suspension and the position G of the center of gravity of the muffler  14 , a moment M is generated around the position Z of the suspension, thereby, the excessive force acts on the connection portion X of the exhaust pipe  13  with the engine  5  and the connection portion Y of the exhaust pipe  13  with the muffler  14 .  
         [0037]    According to the present embodiments, without taking measures such as reinforcement of the connection portion X of the exhaust pipe  13  with the engine  5  and the connection portion Y of the exhaust pipe  13  with the muffler  14  and the installation of the shock absorbing member, an increase in excessive support members is prevented from occurring and a sharp rise in cost can be restrained.  
         [0038]    In the meantime, various shapes or dimensions of respective support members shown in the embodiment described above are just one example, and they are variously changeable according to the requirements in design or the like.  
         [0039]    For example, in the embodiment described above, it exemplifies a case where the exhaust pipe  13  and the muffler  14  constituting the exhaust pipe system are connected with each other at their respective end portions. However, in a case where it is in such a construction wherein they are integrally formed with each other, since the position of the center of gravity as a whole exhaust pipe system is moved to a side of the engine, to that amount, the installation position of the muffler is necessitated to be moved to the side of the engine.  
         [0040]    Further, the saddle-type vehicle is illustrated as a vehicle, however, the constitution can be applicable to the other kinds of vehicles such as a motorcycle.  
         [0041]    As explained above, according to a mounting structure of an exhaust pipe system in a vehicle of the present invention, in a case where vibration is applied to the exhaust pipe system, durability of the exhaust pipe system can be improved by restraining the generation of a moment around a suspension position of the exhaust pipe system, and an additional measure for a shock absorbing function with respect to various connecting portions of the exhaust pipe system can be eliminated.  
         [0042]    Further, since an operating direction of a load in a suspension position can only be bought together in a vertical direction, in a state where a shock absorbing member is arranged in the suspension position, a direction of the load operating relative to the shock absorbing member constitutes one direction. Therefore, improvement in the durability of the shock absorbing member can also be realized.  
         [0043]    Accordingly, an increase in weight of a vehicle can be restrained, and a sharp rise in cost can also be restrained.  
         [0044]    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.