Patent Document

RELATED APPLICATIONS  
       [0001]     The present application is a continuation-in-part of U.S. patent application Ser. No. 10/278,299, filed Oct. 23, 2002. 
     
    
     BACKGROUND OF THE INVENTION  
       [0002]     The present invention relates to a mount structure for a fluid strut in a vehicle. A resilient bushing is mounted within a mount plate that attaches the mount structure to a vehicle frame. The resilient bushing is formed as a separate piece from the mount plate. Two distinct embodiments allow enlarged surfaces on the resilient bushing to be positioned on opposed ends of a smaller base in the mount plate.  
         [0003]     Various types of vehicle suspensions are employed in modern vehicles. One common type of suspension is a McPherson strut suspension. McPherson struts typically include a hydraulic damper with a knuckle secured to the damper by fasteners. A wheel end is supported on the knuckle. A coil spring is secured to an upper portion of the strut and extending between the strut and a mount structure which mounts to the vehicle frame.  
         [0004]     The conventional mount structure has a first upper plate, known as the “rate” plate, which is bolted to a rod on the strut. A second lower plate or “jounce bumper” is secured on the rod at a lower position. A resilient bushing is secured between the two plates, and has radially outwardly extending portions for contacting the jounce bumper and the rate plate. A mount plate is secured to a vehicle frame to mount the resilient bushing to a vehicle frame. Typically, the resilient bushing contacts the jounce bumper and the rate plate. The radially outwardly extending portions have a larger diameter than an inner bore of the mount plate.  
         [0005]     Another feature of a lower one of the radially outwardly extending portions of the resilient bushing is that it secures a bearing seat onto the mount plate.  
         [0006]     In the prior art, since the resilient bushing has been molded as a one piece item to the mount plate, molds have not been able to make as many parts as would be desirable. The surface area of each part has been relatively large, as required by the mount plate. Further, the requirement that there be a single component has restricted the designer in designing desired shapes to the components.  
       SUMMARY OF THE INVENTION  
       [0007]     In a disclosed embodiment of this invention, mounting structure for a strut includes a mount plate for securing a mount structure to a vehicle frame. A resilient bushing is received as a separate component from the mount plate, and has a portion mounted within an inner bore formed within the mount plate. A bearing seat is captured between a lower radially outwardly extending surface of the resilient bushing and the mount plate.  
         [0008]     In one embodiment, this bearing seat has a radiused lower surface to facilitate movement of a radially outwardly extending upper portion of the resilient bushing through the inner bore in the mount plate.  
         [0009]     In a second embodiment, the resilient bushing is formed of two pieces with one being brought upwardly and one being brought downwardly into the inner bore in the mount plate. A nut and threaded end of a rod of the strut secure the plates to hold the resilient bushing in compression when the component is fully assembled.  
         [0010]     These and other features of the present invention can be best understood from the following specification and drawings, the following of which is a brief description. 
     
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0011]      FIG. 1  is a general perspective view of a vehicle suspension.  
         [0012]      FIG. 2  is a sectional view of a mount system according to the present invention.  
         [0013]      FIG. 3  is a side perspective view of a bushing for the mount system illustrated in  FIG. 2 .  
         [0014]      FIG. 4  is a top perspective view of the bushing illustrated in  FIG. 3 .  
         [0015]      FIG. 5  is a sectional view of another mount system according to the present invention.  
         [0016]      FIG. 6  is a side perspective view of a bushing for the mount system illustrated in  FIG. 5 .  
         [0017]      FIG. 7  is a top perspective view of the bushing illustrated in  FIG. 6 .  
         [0018]      FIG. 8A  is a sectional view of the  FIG. 5  mount system in a first assembly condition.  
         [0019]      FIG. 8B  is a sectional view of the mount system of  FIG. 8A  in a second assembly condition.  
         [0020]      FIG. 9A  is a sectional view of the  FIG. 3  mount system in a first assembly condition.  
         [0021]      FIG. 9B  is a sectional view of the mount system of  FIG. 9A  in a second assembly condition.  
     
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT  
       [0022]      FIG. 1  illustrates a general perspective view of a vehicle suspension  10  utilizing a fluid strut such as a McPherson strut  12  which defines an axis A. The strut  12  includes upper  14  and lower  16  portions. The upper portion  14  supports a spring  18  such as a coil spring. The upper portion  14  is supported on the vehicle frame (illustrated schematically at  22 ) by a resilient mount system  24 .  
         [0023]     The spring  18  is retained between the mount system  24  and a fixed lower spring mount  26  attached to the strut  12 . Strut  12  provides hydraulic dampening for a wheel knuckle  28  mounted at the lower portion  16  through a bracket  29  or the like. The knuckle  28  supports a brake assembly  30  and a wheel (not shown) as is well known. The strut  12  may rotate to accommodate a steering input, as is also generally known in the art.  
         [0024]     Referring to  FIG. 2 , a radial sectional view, which passes through axis A, further illustrates the mount system  24 . The upper portion  14  of the strut  12  preferably includes a rod  31  having a threaded section  32  of a smaller diameter to define a step  34 . A jounce bumper  36  forms a lower portion of mount system  24 . The jounce bumper  36  is located upon the threaded section  32  adjacent the step  34 .  
         [0025]     An annular upper retention plate, or rate plate,  38  forms an upper portion of mount system  24 . Rate plate  38  is separated from the jounce bumper  36  by a resilient bushing  40 . Preferably, a nut  42  is threaded upon the threaded section  32  to compresses the resilient bushing  40  between the rate plate  38  and the jounce bumper  36 . The rate plate  38  and the jounce bumper  36  are preferably cup shaped members with their open ends facing away from each other. The resilient bushing  40  of the mount system  24  resiliently retains the strut  12  with a cylindrical frame opening  44  in a rigid mount plate  122 , which is attached to the vehicle frame  22 .  
         [0026]     A bearing seat  46  is mounted about the cylindrical frame opening  44  to provide support for bearing  102  and to assist in the insertion of the resilient bushing  40  by covering an edge  47  of the mount plate  122  with a radial pilot surface  200 . Edge  47  may be relatively sharp while an angled annular upper frame area  49  opposite thereto is of a radiused shape. The radial pilot surface  200  is located adjacent to the relatively sharp edge  47  to pilot installation of the resilient bushing  40  during assembly, as will be explained below. This surface also facilitates centering of the resilient bushing  40  during operation of the strut  12 .  
         [0027]     The bearing seat  46  generally includes an annular section  210  defined about the axis A, and a mount section  212  transverse to the annular section  210 . The annular section  210  is received over and around the mount plate  122 . The mount section  212  extends to an annular frame area  49  to provide support for bearing  102 . Notably, because the strut  12  is typically installed at an angle relative the vehicle frame  22 , the mount section  212  defines a bearing seating surface for the bearing  102  that is not perpendicular to the axis A. It should be understood that various relationships may be provided by the bearing seat  46  and the angled relationship illustrated in the disclosed embodiment shall not be limiting.  
         [0028]     The bearing seat  46  is also at least partially retained by the resilient bushing  40 . A radially outwardly extending lip  100  of the resilient bushing  40  extends beneath the bearing seat  46  to provide this retention feature. It should be understood that the bearing seat  46  and the resilient bushing  40  extend about axis A such that the bearing seat  46  also serves to pilot or position the resilient bushing  40  during assembly ( FIG. 9A ). Various vehicle frame and suspension structures will benefit from the mount systems of the present invention, and the present invention is not limited to the illustrated embodiment.  
         [0029]     Referring to  FIG. 3 , the resilient bushing  40  generally includes a central section  107 , an upper radially outwardly extending lip  105  and the lower radially outwardly extending lip  100 . Notably, the central section  107  defines a diameter that is less than that of the lips  100 ,  105  such that the bushing  40  has a generally hourglass shape. Preferably, the intersections between the central section  107  and the upper and lower radially outwardly extending lips  100 ,  105  are radiused and are received adjacent the frame area  49  and the radial pilot surface  200  ( FIG. 2 ). One feature of the upper radially outwardly extending lip  105 , is to provide a contact surface between the rate plate  38  and the mount plate  122 . Similarly, the lower radially outwardly extending lip  100  provides a contact surface between the jounce bumper  36  and the bearing seat  46 .  
         [0030]     The resilient bushing  40  may be provided with internal support from an optional annular carrier  48 . The annular carrier  48  is preferably a rigid member surrounded by the resilient bushing  40  ( FIG. 3 ). That is, the annular carrier  48  is essentially encapsulated by the resilient bushing  40 . “Encapsulated” as defined herein means the resilient bushing  40  essentially surrounds the annular carrier  48 , however, lip edge portions  50  or the like on the annular carrier  48  can extend at least partially through the resilient bushing  40 . As shown, portions of the resilient bushing  40  are both radially inward and radially outward of the annular carrier  48 . The annular carrier  48  is preferably cup shaped, facing outward relative to axis A, and essentially forms a hub upon which the resilient bushing  40  is molded.  
         [0031]     A rigid annular member  52  is mounted within an inner diameter  53  ( FIG. 2 ) of the resilient bushing  40  ( FIG. 4 ). The annular member  52  is a rigid bushing that defines the distance between the rate plate  38  and the jounce bumper  36 . That is, a portion of the rate plate  38  and the jounce bumper  36  contact the annular member  52  such that a proper compression is applied to the resilient bushing  40  when the nut  42  is threaded upon the threaded section  32 .  
         [0032]     In this embodiment, the resilient bushing  40 , the annular carrier  48 , and the annular member  52  are formed of two-pieces that are preferably mirror images when reflected through an equator S ( FIG. 2 ). The two-piece structure allows rapid assembly in cylindrical frame opening  44 .  
         [0033]     As known in the art, bearing seat  46  supports a bearing  102 . A spring seat  104  ( FIG. 5 ) is mounted on bearing  102  and spring  18  is supported on spring seat  104 . The details of this structure are as known in the art and form no part of this invention.  
         [0034]     Referring to  FIG. 5 , a radial sectional view, which passes through axis A of another mount system  24 ′, is illustrated. Mount system  24 ′ includes a one-piece resilient bushing  54 , an optional annular carrier  66 , and an annular member  52 ′. The resilient bushing  54 , the annular carrier  66 , and the annular member  52 ′ are each a single component.  
         [0035]     The annular carrier  66  is preferably cylindrical to assist the one-piece resilient bushing  54  with insertion through the cylindrical frame opening  44  in the mount plate  122 . That is, the annular carrier  66  is generally tubular rather than having the cup shape described above, as the resilient bushing  54  is one-piece rather than two-piece. The annular member  52 ′ is mounted within an inner diameter  53 ′ of the resilient bushing  54  and functions as described above. See  FIG. 7  also.  
         [0036]     Referring to  FIG. 6 , the one-piece resilient bushing  54  preferably includes an arcuate chamfered surface on upper lip  105 ′. This surface assists in inserting the resilient bushing  54  past the bearing seat  46  and into the cylindrical frame opening  44  of the mount plate  122 . A radially outwardly extending lip  100 ′ generally receives and retains bearing seat  46 .  
         [0037]     As can be appreciated from either  FIG. 2  or  FIG. 5 , a radial pilot surface  200  of the bearing seat  46  is non-parallel and non-perpendicular to the axis A. In fact, as disclosed, the surface is preferably an annular radial pilot which defines a radius. The surface creates a pilot space that assists in insertion of the resilient bushings  40 ,  54  within the bearing seat  46  and through the mount plate  122 . In particular with the embodiment of  FIG. 6 , this surface facilitates initial passage of the enlarged upper lip  105 ′ through the inner periphery of the mount plate  122  and the bearing seat  46 . The upper outwardly extending lips  105 ,  105 ′ thereafter sit atop the mount plate  122 .  
         [0038]     Referring to  FIG. 8A , the mount system  24  of  FIGS. 5-7  is illustrated in a partially assembled condition. The mount plate  122  is mounted to a vehicle frame. The bearing seat  46  is located over the cylindrical frame opening  44  such that the radial pilot surface  200  extends adjacent the edge  47 . In this way, the bearing seat  46  facilitates installation of the resilient bushing  54  while minimizing the potential for damage as the radially outwardly extending lip  105 ′ of the resilient bushing  54  is compressed to pass through the smaller diameter cylindrical frame opening  44  until reaching an installed position. The resilient bushing  54  is maintained slightly in compression (illustrated schematically by the dashed line in  FIG. 8B ) once installed.  
         [0039]     Although  FIG. 8A  utilizes the resilient bushing  54  of  FIG. 5 , it should be understood that installation is likewise generally similar for the embodiment of  FIG. 2 . Referring to  FIG. 9A , the resilient bushing  40  is symmetrical about the equator S to define a two-piece structure  40   a ,  40   b . The two-piece structure provides for assembly into the cylindrical frame opening  44  from each side of the mount plate  122 . Here, the bearing seat  46  need not provide as significant of the pilot function as described with reference to  FIGS. 8A, 8B  but does provide for centering alignment within the cylindrical frame opening  44  during operation. The bearing seat  46  also minimizes stresses upon the resilient bushing which may otherwise occur should the edge  47  be exposed as in conventional bearing seat arrangements known in the prior art. Here too, the resilient bushing  40  is maintained in compression (illustrated schematically in  FIG. 9B ) once installed. Furthermore, the two-piece structure  40   a ,  40   b  of the resilient bushing  40  is retained together by the interaction between the step  34 , nut  42 , rate plate  38 , and jounce bumper  36  ( FIG. 2 ).  
         [0040]     The foregoing description is exemplary rather than defined by the limitations within. Many modifications and variations of the present invention are possible in light of the above teachings. The preferred embodiments of this invention have been disclosed, however, one of ordinary skill in the art would recognize that certain modifications would come within the scope of this invention. It is, therefore, to be understood that within the scope of the appended claims, the invention may be practiced otherwise than as specifically described. For that reason the following claims should be studied to determine the true scope and content of this invention.  
         [0041]     Although a preferred embodiment of this invention has been disclosed, a worker of ordinary skill in this art would recognize that certain modifications would come within the scope of this invention. For that reason, the following claims should be studied to determine the true scope and content of this invention.

Technology Category: b