Abstract:
A multi-axis isolator assembly comprises an upper base, a lower base having a first tubular member, first and second isolation layers, and an isolator. First and second isolation layers and isolator are disposed between the upper and lower bases. The first isolation layer and isolator substantially circumscribe the first tubular member of the lower base. The second isolation layer substantially circumscribes the isolator. This abstract is submitted with the understanding that it will not be used to interpret or limit the scope or meaning of the claims.

Description:
TECHNICAL FIELD  
       [0001]     The present invention relates to a multi-axis isolator and assembly. In particular, the present invention relates to a multi-axis isolator and assembly for securing a heat shield to an exhaust manifold while isolating vibrational forces from the exhaust manifold.  
       BACKGROUND OF THE INVENTION  
       [0002]     Objects attached to a vehicular engine experience vibrational forces generated by the operation of the engine. A conventional method of damping vibration, and in turn reducing noise, is with a T-shaped mount. A typical T-shaped mount includes a metal cylindrical sleeve that runs vertically the height of the mount to provide structural rigidity to the mount. A metal bolt passes through the metal sleeve for securing the mount to the engine. Various materials, including rubber or metal mesh, surround the cylindrical sleeve of the mount to assist in dampening the vibrations.  
         [0003]     A number of problems have become apparent with the use of conventional T-shaped mounts with rubber. For example, rubber has a relatively short service life. Because of the shearing and torquing forces applied by the motor to the mount, the rubber has a tendency to collapse in a relatively short time. Moreover, rubber also has a tendency to deteriorate when it comes into contact with gasoline, oil, grease, road salt, or other chemicals and solvents present in an engine environment. Metal mesh mounts have relatively low load carrying ability in radial directions. Therefore, conventional metal mesh mounts do not sufficiently attenuate vibrations in the radial direction.  
       SUMMARY OF THE INVENTION  
       [0004]     To overcome the above identified problems and other problems associated with conventional mounting assemblies, the present invention is directed to a multi-axis isolator assembly. The multi-axis isolator assembly includes an upper base, a lower base having a first tubular member, first and second isolation layers, and an isolator. The first and second isolation layers and isolator are disposed between the upper and lower bases. The first isolation layer and isolator substantially circumscribe the first tubular member. The second isolation layer substantially circumscribes the isolator. 
     
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0005]     The present invention will now be described, by way of example, with reference to the accompanying drawings, in which:  
         [0006]      FIG. 1  is a cross sectional view of a mounting assembly according to one embodiment of the present invention.  
         [0007]      FIG. 2  is an expanded view of the mounting assembly according of  FIG. 1 .  
         [0008]      FIG. 3  is a perspective view of an isolator according to an alternative embodiment of the present invention.  
         [0009]      FIG. 4  is a cross-sectional view of a mounting assembly including the alternative isolator according to  FIG. 4 .  
         [0010]      FIG. 5  is a cross-sectional view of a mounting assembly according to an alternative embodiment of the present invention. 
     
    
     DESCRIPTION OF THE PREFERRED EMBODIMENT  
       [0011]     Referring to  FIGS. 1 and 2 , a mounting assembly  10  is shown according to one embodiment of the present invention. Mounting assembly  10  includes upper and lower bases  12 ,  14  respectively, first and second isolation layers  16 , 18  respectively, and an isolator  20 . Lower base  14  has an integral first tubular member  22 . Upper base  12  includes a lip  24  and an integral second tubular member  26 , defining a central opening  28 . Central opening  28  extends from an outer surface  30  of upper base  12  to an outer surface  32  of lower base  14 .  
         [0012]     First and second isolation layers  16 ,  18  and isolator  20  are disposed between upper base  12  and lower base  14  and positioned circumferentially around central opening  28 . First isolation layer  16  has upper and lower surfaces  34 ,  36  and a cylindrical aperture  38 . Aperture  38  of first isolation layer  16  extends from upper surface  34  to lower surface  36  of first isolation layer  16 . Second isolation layer  18  has upper and lower surfaces  40 ,  42  and a cylindrical aperture  44 . Aperture  44  of second isolation layer  18  extends from upper surface  40  to lower surface  42  of second isolation layer  18 . Likewise, isolator  20  has upper and lower surfaces  46 ,  48  and a cylindrical aperture  50 . Similarly, cylindrical aperture  50  extends from upper surface  46  to lower surface  48  of isolator  20 .  
         [0013]      FIG. 2  is an expanded view of mounting assembly  10  in an installed position on a mounting surface (not shown). During installation of mounting assembly  10 , lower base  14  rests upon the mounting surface. First isolation layer  16  is placed on lower base  14 . First tubular member  22  passes through aperture  38  of first isolation layer  16 . Fully installed, lower surface  36  of first isolation layer  16  rests upon an inner surface  52  of lower base  14 . Inner surface  38   a  of aperture  38  of first isolation layer  16  abuts outer surface  22   a  of first tubular member  22 .  
         [0014]     Isolator  20  is then disposed over first isolation layer  16 . In the same manner as first isolation layer  16 , first tubular member  22  slides through aperture  50  of isolator  20 . Fully installed, lower surface  48  of isolator  20  rests upon upper surface  34  of first isolation layer  16 . Additionally, inner surface  50   a  of aperture  50  of isolator  20  abuts outer surface  22   a  of first tubular member  22 .  
         [0015]     Next, a heat shield  54  is installed to the mounting assembly  10 . Heat shield  54  includes upper and lower surfaces  56 ,  58  and a lipped aperture  60 . Tubular member  22  of lower base  14  slides through lipped aperture  60  of heat shield  54 . Additionally, isolator  20  passes through lipped aperture  60  of heat shield  54 . Fully installed, lower surface  58  of heat shield  54  rests upon upper surface  34  of first isolation layer  16 . Inner surface  60   a  of the lipped aperture  60  of heat shield  54  abuts outer surface  20   a  of isolator  20 .  
         [0016]     Next, second isolation layer  18  is placed over heat shield  54 . Second isolation layer  18  slides past first tubular member  22 . Lower surface  42  of second isolation layer  18  rests upon upper surface  56  of heat shield  54 . Inner surface  44   a  of aperture  44  of second isolation layer  18  abuts outer surface  60   b  of lipped aperture  60  of heat shield  54 . Fully installed, lipped aperture  60  of heat shield  54  is disposed between isolator  20  and second isolation layer  18 .  
         [0017]     Finally, upper base  12  is placed over second isolation layer  18 . Second tubular member  26  slides into first tubular member  22 , such that outer surface  26   a  of second tubular member  26  abuts inner surface  22   b  of first tubular member  22 . In a fully installed position, second tubular member  26  extends to the mounting surface and upper base  12  rests upon upper surface  40  of second isolation layer  18 . Lip  24  of upper base  12  abuts outer surface  18   a  of second isolation layer  18 , such that second isolation layer  18  is nestled between heat shield  54  and lip  24  of upper base  12 .  
         [0018]     Referring to  FIGS. 3 and 4 , first isolation layer  16  and isolator  20  are shown according to the alternative embodiment of the present invention. First isolation layer  16  and isolator  20  are constructed as a single isolator  20 ′. Unitary isolator  20 ′ provides additional advantages over first isolation layer  16  and isolator  20 . For instance, unitary isolator  20 ′ results in a reduced number of parts for mounting assembly  10 . Moreover, the reduced number of parts results in easier assembly of mounting assembly  10 .  
         [0019]      FIG. 5  depicts an alternative embodiment of the present invention. Mounting assembly  10 ′ substantially incorporates the features of mounting assembly  10  of  FIGS. 1 and 2 . However, second tubular member  26 ′ of mounting assembly  10 ′ contains a crimp or dimple  62  for engaging a fastener  64 . Dimple  62  may be positioned anywhere within central opening  28 ′ of second tubular member  26 ′, so long as dimple  62  engages fastener  64 . Further, while the present invention contains a dimple  62 , it is appreciated that any form of indentation may be created on second tubular member  26 , so long as the indentation engages fastener  64 . Fastener  64 , in turn, secures heat shield  54  to the mounting surface. Any conventional fastener  64  known in the art for securing a heat shield  54  to a mounting surface may be utilized.  
         [0020]     Referring to  FIGS. 1-5 , first and second isolation layers  16 ,  18 , and isolator  20  are made from a wire mesh material. The wire mesh material allows first and second isolation layers  16 ,  18  and the isolator  20  to work in high temperature environments. First and second isolation layers  16 ,  18  and isolator  20  cooperate with the mass of heat shield  54  to act as a tuned system. The spring rate of the first and second isolation layers  16 ,  18  and isolator  20 , along with the mass of heat shield  54 , determine the natural frequency of the tuned system. The result is any forced vibrations from the mounting surface, above the natural frequency, are not transmitted by first and second isolation layer  16 ,  18  and isolator  20  to heat shield  54 . Heat shield  54  is protected from vibrations of the mounting surface. Isolation layers  16 ,  18  and isolator  20  or  20 ′ of the present invention provide many advantages over conventional mounting assemblies. Mounting assembly  10  and  10 ′ improves isolation of vibrations in the radial direction of isolator  20 . This is a benefit when the axis of isolator  20  cannot be attached in an orientation parallel to the primary vibrations of the mounting surface. Furthermore, non-primary vibrations commonly may occur in different axis. Isolator  20  can also prevent non-primary vibrations from being transmitted to heat shield  54 . It can be appreciated that unitary isolator  20 ′ can replace first isolation layer  16  and isolator  20  without compromising the performance of mounting assembly  10  or  10 ′ while obtaining the same benefits and improvements.  
         [0021]     Upper and lower bases  12 ,  14  may be stamped, turned metal, powdered metal or any other suitable material for high temperature environments. Lower base  14  acts as a base washer for mounting assembly  10 . Therefore, there is no need for additional base washers to be placed on the mounting surface before attaching the mounting assembly  10 . The present invention results in a mounting assembly  10  having fewer parts than conventional mounting assemblies. Additionally, having first and second tubular members  22 ,  26  integral with upper and lower bases  12 ,  14 , respectively, eliminates the need for a separate inner collar from the base washer, as present in conventional mounting assemblies. The fewer parts of the present invention not only result in cost savings, but also increase the ease of assembling the mounting assembly  10 . Furthermore, first and second tubular members  22 ,  26  act as load bearing columns for first and second isolation layers  16 ,  18  and isolator  20 .  
         [0022]     Lipped end  24  of upper base  12  provides greater surface area for upper base  12  to contact second isolation layer  18 . This allows second isolation layer  18  to assist isolator  20  with isolating radial vibrations. Therefore, the load on isolator  20  is lessened, resulting in a longer life cycle of isolator  20  and mounting assembly  10 . Similarly, lipped aperture  60  of heat shield  54  provides greater surface area for second isolation layer  18  and isolator  20  to contact heat shield  54 . The increased contact results in isolation layer  18  and isolator  20  being able to isolate more vibrational forces from heat shield  54 .  
         [0023]     While the present invention is directed towards a mounting assembly  10  or  10 ′ for a heat shield  54  of an exhaust manifold (not shown), it can be appreciated that the present invention is not limited in application to a heat shield for an exhaust manifold. The present invention can be practiced in any environment that requires isolating vibrational forces from a vibrational surface. For example, mounting assembly  10  or  10 ′ can be used in the field of household electrical appliances or heavy machinery.  
         [0024]     While the invention has been specifically described in connection with certain specific embodiments thereof, it is to be understood that this is by way of illustration and not of limitation, and the scope of the appended claims should be construed as broadly as the prior art will permit.