Patent Publication Number: US-2006005536-A1

Title: Exhaust decoupler

Description:
BACKGROUND OF THE INVENTION  
      1. Field of the Invention  
      The present invention relates to a decoupler of an exhaust pipe, and more particularly to a decoupler including a bellows having one end coupled between a sleeve and an outer cap, the other end coupled to the inner circumferential surface of an inner cap, side corrugations connected to the outer cap and the inner cap and smaller than a middle corrugation so as to form a rounded overall shape of the bellows, the inner cap formed with curved surfaces corresponding to the overall shape of the bellows, the outer cap formed with bending portions so as to have corners, buffering members supported by the curved surfaces of the inner cap and the inner surfaces of the bending portions of the outer cap, and spaces formed in the insides of the bending portions, so that various stresses due to impact, vibration, and heat distortion, are absorbed by the spaces, and the deformation of the decoupler can be prevented.  
      2. Description of the Related Art  
      Generally, a vehicle engine is connected with an exhaust pipe having a muffler to exhaust the exhaust gas. At the connection point of the exhaust pipe is installed a decoupler, as a connecting device. The decoupler prevents vibration from being transmitted to the vehicle body by absorbing vibration caused by explosions in the engine, and prevents external shock from being transmitted to the engine. Moreover, the decoupler absorbs displacement caused by vibration and impact load and buffers heat distortion. The decoupler includes a bellows, a sleeve, an outer cap for enclosing the outside of the bellows, and an inner cap. The bellows has a plurality of corrugations and is disposed between an engine and the exhaust pipe coupled to the vehicle body. The sleeve is inserted into one side of the bellows to be connected to the engine. The inner cap is disposed between the bellows and the outer cap, and is spaced from the outer cap.  
      The decoupler constructed as described above prevents vibration from being transmitted to the vehicle body by absorbing the vibration generated from the engine, and prevents vibration generated from the vehicle body due to uneven road conditions from being transmitted to the engine, so as to protect the engine. The decoupler must absorb the vibration and displacement generated at the exhaust system of the vehicle. Stress and displacement absorbed by the decoupler may include various stresses, such as tensile stress, compressive stress, bending stress, and torsional stress, and excessive displacement generated in every direction.  
      The decoupler includes a bellows disposed between rims and a buffering member, for enclosing the outer surface of the engine. The rims and the buffering members absorb vibration of the engine, the expansion displacement in the longitudinal direction generated by impact when in motion, and bending displacement when the central axes of exhaust connecting devices are deviated from each other. Since the inner cap coupled to the engine is separated from the outer cap coupled to the exhaust pipe, the buffering member and the bellows are formed with respective elastic portions. The elastic portions are disposed between the inner cap and the outer cap and support the inner cap and the outer cap, so as to absorb the deformation, vibration, and impact stress.  
      Therefore, in the decoupler, it is very important that the bellows and a wire mesh, of which one end is connected to the engine and the other end is connected to the exhaust pipe, allow the exhaust gas to flow through a central part thereof, and are expanded to absorb the impact and the deformation generated between the engine and the exhaust pipe.  
      To overcome the above-described disadvantage, extensive research and a variety of approaches have been proposed. A conventional decoupler for connecting an exhaust pipe to an engine, as shown in  FIG. 1 , includes a sleeve  20  coupled to the engine  200 , a bellows coupled to an outer surface of one end of the sleeve  20  which is coupled to the engine  200 , an outer cap  20  installed outside the bellows  10 , an inner cap  40  disposed between the outer cap  30  and the bellows  30  and integrally connected to the other end of the bellows  10 , in which the exhaust pipe  300  is coupled, and supporting wire meshes  500  filled in a space on one end  31  of the outer cap  30 , defined by the outer cap  30  and the inner cap  40 , and a space on one end  41  of the inner cap  40 , defined by the outer cap  30  and the inner cap  40 .  
      However, the above-mentioned decoupler does not sufficiently manage impact, vibration, and heat distortion, and is not flexible because of the deformation of the inner cap  40  and/or the outer cap  30 , so that the decoupler cannot fulfill its designed functions.  
      The development of the above-described decoupler is shown in  FIG. 2 . As shown in  FIG. 2 , the development of the decoupler includes a sleeve  20  coupled to the engine  200 , a bellows coupled to an outer surface of one end of the sleeve  20  which is coupled to the engine  200 , an outer cap  20  installed outside the bellows  10 , an inner cap  40  disposed between the outer cap  30  and the bellows  30  and integrally connected to the other end of the bellows  10 , to which the exhaust pipe  300  is coupled, supporting wire meshes  500  filled in a space on one end of the outer cap  30 , defined by the outer cap  30  and the inner cap  40 , and a space on one end of the inner cap  40 , defined by the outer cap  30  and the inner cap  40 , and shock-absorbing wire meshes  600  filled the outside spaces of the supporting wire meshes  500 , defined between the supporting wire meshes  500 . However, the above-mentioned decoupler, does not sufficiently manage impact, vibration, and heat distortion, and is not flexible because of the deformation of the inner cap  40  and/or the outer cap  30 , so that the decoupler cannot fulfill its designed functions.  
     SUMMARY OF THE INVENTION  
      Therefore, the present invention has been made in view of the above problems, and it is an object of the present invention to provide a decoupler including a bellows having one end coupled between a sleeve and an outer cap, the other end coupled to the inner circumferential surface of an inner cap, side corrugations connected to the outer cap and the inner cap and smaller than a middle corrugation, to form a rounded whole shape of the bellows, the inner cap formed with curved surfaces corresponding to the rounded overall shape of the bellows, the outer cap formed with bending portions to have corners, buffering members supported by the curved surfaces of the inner cap and the inner surfaces of the bending portions of the outer cap, and spaces formed in the insides of the bending portions, so that various stresses due to impact, vibration, and heat distortion, are absorbed by the spaces. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
      These and/or other objects and advantages of the present invention will become apparent and more readily appreciated from the following description of the embodiments, taken in conjunction with the accompanying drawings, in which:  
       FIG. 1  is a cross-sectional view of a conventional decoupler;  
       FIG. 2  is a cross-sectional view of another conventional decoupler;  
       FIG. 3  is a partial cross-sectional view of a decoupler according to the present invention; and  
       FIG. 4  is a schematic view illustrating installation of the decoupler according to the present invention and the conventional decoupler to the vehicle engine. 
    
    
     DESCRIPTION OF THE PREFERRED EMBODIMENTS  
      Hereinafter, a decoupler according to the present invention will be described in connection with the accompanying drawings.  
      As shown in  FIG. 3 , the decoupler includes a corrugated bellows  10 , a sleeve  20 , an outer cap  30 , an inner cap  40 , and buffering members  50  made of wire meshes.  
      The corrugated bellows  10  is formed with repeated wave-formed corrugations. The sleeve  20  is inserted into the bellows  10  and protects the bellows  10  against exhaust gas. The sleeve  20  has one end with a large diameter fixed to an inner surface of one end of the bellows  10 , and a free end of a small diameter spaced apart from an inner surface of the bellows  10 .  
      The outer cap  30  encloses the outer side of one end of the bellows  10  where the sleeve  20  is coupled. The inner cap  40  is installed between the outer cap  30  and the bellows  10 , and is also coupled to the other end of the bellows  10 , so as to enclose the outside of the bellows  10 .  
      The buffering members  50  are installed in a space on one end of the inner cap  40 , defined between an outer surface of the inner cap  40  and an inner surface of the outer cap  30 , and in a space on one end of the outer cap  30 , defined between the outer surface of the inner cap  40  and the inner surface the outer cap  30 , so as to support the inner cap  40  and the outer cap  30  and to maintain air tightness between the inner cap  40  and the outer cap  30 .  
      The corrugations  11  formed at sides of the bellows  10  are smaller than corrugations  12  formed at a middle portion of the bellows  10 . Thus the bellows forms a gentle curved line R.  
      The inner cap  40  has curved surfaces  45  respectively formed at a leading end and the other end thereof, so that the curved surfaces of the inner cap  40  correspond to the curved line formed by the corrugations  11  and  12  of the bellows  10 . The inner cap  40  encloses surfaces of the corrugations  11  and  12  to be adjacent to the surfaces of the corrugations  11  and  12  of the bellows  10 .  
      However, it is very important that the inner cap  40  does not interfere with the bellows  10 .  
      The outer cap  30  has L-shaped cross-sectional bending portions  35  respectively formed at the end  31  of the outer cap  30  and at a portion corresponding to the end  41  of the inner cap  40 , and the end  31  of the outer cap  30  has an inner diameter sufficient to be spaced apart from an outer circumference of the inner cap  40 , so as to maintain a gap between the outer surface of the inner cap  40  and the end of the outer cap  30 . Thus, the outer cap  30  properly manages the tensile stress and the bending stress.  
      The lower surfaces  51  of the buffering members  50  are closely attached to an outer curved surface of the inner cap  40 , upper surfaces  52  of the buffering members  50  are closely attached to upper inside surfaces of the bending portions  35  and lateral surfaces  53  of the buffering members  50  are closely attached to lateral inner surfaces of the bending portions, so as to define buffering spaces  60  between the buffering members  50  and the bending portions  35 .  
      Reference numeral  200  indicates the vehicle engine, and reference numeral  300  indicates the exhaust pipe of the vehicle having the muffler.  
      When the decoupler according to the present invention will be used by being installed to the vehicle engine  200 , as shown in  FIG. 4 , there may appear various situations caused by road conditions in the traveling and heat distortion due to the heat of the exhaust gas generated from the engine  200 . Here, the effect of the decoupler according to the present invention will be described by using some situations as examples.  
      The sleeve  20  having a free end is the first to absorb the heat generated from the exhaust gas, the rest of the heat is transmitted to the bellows  10 . The corrugations of the bellows  10  absorb stress caused by the heat as much as possible. Moreover, the bellows  10  absorbs the vibration due to the explorations in the engine  200  so as to prevent the vibration from being transmitted to the exhaust pipe  300 .  
      In this state, when various stresses, such as vibration, bending stress, tensile stress, and the like, generated from wheels of the vehicle when in motion are transmitted to the decoupler via the exhaust pipe  300 , the bending stress and the torsional stress are absorbed by the deformation and restoration of the bellows  10  by which the wire mesh buffering members  50 , disposed between the outer cap  30  and the inner cap  40 , are slid over the outer surface of the inner cap  40 . The tensile stress and the impact stress are absorbed in a manner that the wire mesh buffering members  50 , disposed between the inner cap  40  and the outer cap  30 , are deformed and restored in the spaces  60  defined between the outer cap  30  and the bending portions  35 .  
      As described above, the bellows  10  is installed such that one end of the bellows  10  is coupled between the sleeve  20  and the outer cap  30  and the other end of the bellows  10  is coupled to the inner circumferential surface of the inner cap  40 . The bellows  10  has the side corrugations  11 , connected to the outer cap  30  and the inner cap  40 , smaller than the middle corrugation  12 , so as to form a rounded overall shape. The inner cap  40  is formed with the curved surfaces  45  corresponding to the overall shape of the bellows  10 . The outer cap  30  is formed with the bending portions  35  so as to have corners. The buffering members  50  are supported by the curved surfaces  45  of the inner cap  40  and the inner surfaces of the bending portions  35  of the outer cap  30 . The spaces  60  are formed in the insides of the bending portions  35 , so that various stresses due to impact, vibration, and heat distortion, are absorbed in the spaces  60 . Thus, the deformation of the decoupler can be prevented so as to reduce wearing of the decoupler and frictional noise and to enhance the durability of the decoupler.  
      Although the preferred embodiments of the present invention have been disclosed for illustrative purposes, those skilled in the art will appreciate that various modifications, additions and substitutions are possible, without departing from the scope and spirit of the invention as disclosed in the accompanying claims.