Abstract:
A vehicle suspension assembly that includes first and second main beams each having a first end operably coupled to a vehicle frame, and a second end having a cavity formed therein, and first and second extension members each having an aperture extending therethrough, wherein the first and second extensions are interference-fit within and extend outwardly from the cavity of the first and second main beams, respectively. The assembly further including a torsion member having apertured first and second ends that receive the first and second extension members therein, and threaded mechanical fasteners extending through the apertures of the first and second extension members and engage nuts that are frictionally engaged by the first and second main beams.

Description:
CROSS REFERENCE TO RELATED APPLICATION  
       [0001]     This application claims the benefit of U.S. Provisional Application No. 60/680,558, filed May 13, 2005, entitled VEHICLE SUSPENSION ASSEMBLY, which is hereby incorporated herein by reference in its entirety. 
     
    
     BACKGROUND OF THE PRESENT INVENTION  
       [0002]     The present invention relates to a vehicle suspension assembly, and in particular to a heavy-duty suspension system with increased load capacity and decreased weight.  
         [0003]     Various suspension systems utilizing air springs have been developed for semi-tractor trailers and other heavy vehicles. These systems are typically designed to control the position of the chassis relative to an associated axle and to cushion any movement of the axle with respect to the chassis frame. Although these systems provide excellent chassis control over a wide range of loading conditions, conventional air spring systems typically do not offer acceptable resistance to vehicle roll, as is often experienced when the vehicle turns, nor do they offer acceptable resistance to lateral shifting of the vehicle, such as when the vehicle accelerates or decelerates.  
         [0004]     While specialized components have been added to air spring systems to reduce roll and lateral shift, many of these components add significant weight and cost to the associated suspension system without greatly reducing the roll and lateral shift. Specifically, these designs typically incorporate single-piece trailing arms that require materials meeting torsional and sheer strength requirements, but that also may be tapped and threaded as required. Further, many of these components include complicated designs that are not only expensive to manufacture, but are also difficult to install or replace should damage to the component or related equipment occur. One particular assembly includes stabilizing the related suspension system by securing a torsional beam between a pair of trailing arms by bolts that extend through the torsional beam and into threaded apertures located in the ends of the beams. This particular assembly requires large securing bolts adapted to withstand significant torsional and sheering forces, and further requires the replacement or retapping of a trailing arm should the threads within the bolt receiving aperture become damaged or worn.  
         [0005]     There is a need for a lightweight and inexpensive air spring suspension system that resists roll and lateral shift, will not significantly impact the ride-cushioning characteristics of such suspension system, provides relative increase of structural integrity, and that can further be maintained and repaired quickly and cost effective.  
       SUMMARY OF THE INVENTION  
       [0006]     One aspect of the present invention is a vehicle suspension assembly comprising a first main beam having a first end operably coupled to a vehicle frame, and a second end having a cavity formed therein, a first extension member having an aperture extending therethrough, wherein the first extension is located within and extends outwardly from the cavity of the first main beam, a second main beam having a first end operably coupled to a vehicle frame, and a second end with a cavity formed therein, and a second extension member having an aperture extending therethrough, wherein the second extension is located within and extends outwardly from the cavity of the second main beam. The suspension assembly also includes a torsion member having a first end with a first aperture that receives the first extension member therein, and a second end with a second aperture that receives the second extension member therein. The suspension assembly further includes a first threaded mechanical fastener extending through the aperture of the first extension member and engaging a first nut frictionally engaged by the first main beam thereby coupling the first end of the torsion member with the second end of the first main beam, and a second threaded mechanical fastener extending through the aperture of the second extension member and engaging a second nut frictionally engaged by the second main beam, thereby coupling the second end of the torsion member with the second end of the second main beam.  
         [0007]     Another aspect of the present invention is a method for constructing a main beam assembly for a vehicle suspension assembly that comprises providing a main beam having a first end adapted to be operably coupled to a vehicle frame, and a second end that has an integrally formed cavity therein, and providing an extension member having a first end, a second end adapted to couple with a torsion member of a vehicle suspension assembly, and an aperture extending between the first and second ends of the extension member. The method further includes coupling the extension member with the main beam by compression-fitting the first end of the extension member in the cavity of the main beam, such that the second end of the extension member extends outward from the cavity of the main beam.  
         [0008]     Yet another aspect of the present invention is a vehicle suspension assembly comprising a first main beam that has a first end operably couplable to a vehicle frame, and a second end that has an inwardly extending passage, wherein at least a portion of the passage frictionally engages a first portion of a first fastener, thereby preventing rotation of the first portion of the first fastener, and a second main beam has a first end operably couplable to a vehicle frame, and a second end has an inwardly extending passage, wherein at least a portion of the passage of the second main beam frictionally engages a first portion of a second fastener. The suspension assembly also includes a torsion member having a first end with an aperture extending therethrough and that is operably coupled with the second end of the first main beam by a second portion of the first fastener, wherein the first fastener extends through the aperture of the first end of the torsion member and the passage of the first main beam and is coupled with the first portion of the first fastener, and a second end with an aperture extending therethrough and is operably coupled with the second end of the second main beam by a second portion of the second fastener, wherein the second fastener extends through the aperture of the second end of the torsion member and the passage of the second main beam and is coupled with the first portion of the second fastener.  
         [0009]     The present inventive vehicle suspension assembly maintains the ride-cushioning characteristics of an air spring suspension system, while simultaneously increasing roll and lateral shift resistance. The weight of the assembly is minimized by allowing the use of different materials to construct a single trailing arm or beam. Further, relatively longer and smaller diameter bolts are utilized that are allowed to “stretch” during assembly, thereby compensating for wear on components that may create gaps in the suspension assembly during use. Moreover, by interference-fitting the extension member into the main beam, within a separate component that is then welded to the main beam, potential relaxing of compression loads in the joint between the extension member and the beam is prevented.  
         [0010]     The addition of a pocket or passage that can secure a nut on the bottom side of the main beam aids in assembly as suspension assemblies are typically constructed upside down, and further eliminates the need for a wrench to secure the fastener by frictionally securing a plurality of sides of a fastener. Further, the downward opening orientation of the passage facilitates the drainage of water, snow, and debris from the pocket during normal operating conditions, thus reducing the potential for corrosion. Moreover, the present inventive vehicle suspension assembly is efficient to make and use, economical to manufacture and repair, capable of a long operating life, and particularly well-adapted for the proposed use.  
         [0011]     These and other advantages of the invention will be further understood and appreciated by those skilled in the art by reference to the following written specification, claims and appended drawings. 
     
    
     BRIEF DESCRIPTION OF DRAWINGS  
       [0012]      FIG. 1A  is a top and front side perspective view of the vehicle frame supported by a vehicle suspension assembly embodying the present invention;  
         [0013]      FIG. 1B  is a top and second side perspective view of the vehicle frame supported by the vehicle suspension assembly;  
         [0014]      FIG. 2  is an exploded perspective view of a pair of main beam assemblies of the suspension assembly;  
         [0015]      FIG. 3  is an exploded perspective view of a first alternate embodiment of the main beam assemblies;  
         [0016]      FIG. 4  is a side elevational view of a main beam;  
         [0017]      FIG. 5  is a bottom elevational view of the main beam;  
         [0018]      FIG. 6  is a partial cross-sectional view of a main beam taken through line VI-VI,  FIG. 2 ;  
         [0019]      FIG. 7  is an exploded view of a second alternative embodiment of the main beam assemblies  
         [0020]      FIG. 8  is an exploded perspective view of a third alternative embodiment of the main beam assembly; and  
         [0021]      FIG. 9  is a cross-sectional view of the third embodiment of the main beam assembly. 
     
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS  
       [0022]     For purpose of description herein the terms “upper”, “lower”, “right”, “left”, “rear”, “front”, “vertical”, “horizontal” and derivatives thereof shall relate to the invention as oriented in  FIGS. 1 and 4 . However, it is to be understood that the invention may assume various alternative orientations and step sequences, except where expressly specified to the contrary. It is also to be understood that the specific devices and processes illustrated in the attached drawings, and described in the following specification are exemplary embodiments of the inventive concepts defined in the appended claims. Hence, specific dimensions and other physical characteristics relating to the embodiments disclosed herein are not to be considered as limiting, unless the claims expressly state otherwise.  
         [0023]     The reference numeral  10  ( FIGS. 1A and 1B ) generally designates a vehicle suspension assembly embodying the present invention, and supporting a vehicle frame  12  above a vehicle axle  14  and a plurality of associated ground contacting wheels (not shown). In the illustrated example, the vehicle frame  12  includes a first rail member  16 , and a second rail member  18  extending substantially parallel to the first rail member  16 . The first rail member  16  and the second rail member  18  are each provided a C-shaped cross-sectional configuration including a side wall  20 , a top wall  22  and a bottom wall  24 . The vehicle frame  12  further includes a lateral beam  26  extending orthogonal to the first rail member  16  and the second rail member  18 . The lateral beam  26  is provided an I-shaped cross-sectional configuration including a center wall  28 , a top wall  30  and a bottom wall  32 . The suspension assembly  10  further includes a pair of air springs  116  located between the first and second rail members  16 ,  18  and the axle  14 , respectively. Each air spring  116  includes a flexibly resilient bladder  117 , an upper plate  118  fixedly attached to the associated rail member  16 ,  18  via a connecter bracket  119 , and a bottom plate member  120  fixedly attached to a torsion member, as described below. It should be further noted that the suspension assembly  10  as disclosed herein may be utilized in a plurality of configurations including hydraulic suspension assemblies, coil spring suspension assemblies, air ride suspension assemblies, two-bag air ride suspension assemblies, four-bag air ride suspension assemblies, and the like. It should be noted that the suspension assembly  10  may be used to support other configurations of vehicle frames, and that the vehicle frame  12  is utilized as an example only.  
         [0024]     The vehicle suspension assembly  10  includes a first main beam  42  ( FIG. 4 ) having a first end  44  operably coupled to the frame  12 , and a second end  48  with a cavity  50  ( FIG. 5 ) formed therein, and a first extension member  52  having a first end  53 , a second end  54 , and an aperture  56  extending therethrough. The suspension assembly  10  also includes a second main beam  62  having a first end  64  operably coupled to a vehicle frame  12 , and a second end  68  with a cavity  70  formed therein, and a second extension member  72  having a first end (not shown), a second end  74 , and an aperture  76  extending therethrough. The assembly  10  further includes a torsion member  80  having a first end  82  with a first aperture  84  containing a bushing  85  that receives the first extension member  52  therein, and a second end  86  with a second aperture  88  containing a bushing  89  that receives the second extension member  72  therein. Preferably, the materials utilized to construct the first and second extension members  52 ,  72  are different than the materials used to construct the main beams  42 ,  62 , with the extensions  52 ,  72  being constructed of a strong, wear-resistant material, and the main beams  42 ,  62  being constructed of a strong, relatively lightweight material.  
         [0025]     The suspension assembly  10  further includes a control arm  130  pivotally connected on one end to a top portion of the axle  14  and pivotally connected on the other end to the center wall  28  of the lateral beam  26  of the frame  12 . A track arm  132  is pivotally connected on one end to a support bracket  134  on a top portion of the axle  14  and on the other end to the side wall  20  of the first rail member  16 . A top end  140  of a shock absorber  142  is pivotally connected to a support bracket  144  fixedly attached to the side wall  20  of the first rail member  16 . A bottom end  146  is pivotally connected to a top portion of the second end  48  of the first main beam  42 . Similarly, a top end  150  of a shock absorber  152  is pivotally connected to a support bracket  154  fixedly attached to the side wall  20  of the second rail member  18 . A bottom end  156  is pivotally connected to a top portion of the second end  68  of the second main beam  62 . In addition, the axle  16  is pivotally connected to the first main beam  42  and the second main beam  62 .  
         [0026]     In assembly, the first and second main beams  42 ,  62 , are produced by casting or forging the main beams from an alloy such as steel. The first end  53  of the first extension member  52  is inserted into the cavity  50  such that the second end  54  extends outwardly from the cavity  50 , and is fixedly secured inside the cavity  50  of the first main beam  42  by compression-fitting, such as shrink-fitting, press-fitting, and the like, or adhering, or a combination thereof. In a similar fashion, the first end  73  of the second extension member  72  is inserted into the cavity  70  such that the second end  74  extends outwardly from the cavity  70 , and is fixedly secured inside the cavity  70  of the second main beam  62 . A pair of washers  180 ,  181  each having an aperture with a diameter slightly larger than the outside diameter of the first and second extensions  52 ,  72 , respectively, are positioned over the first extension member  52 ,  72 .  
         [0027]     The first aperture  84  of the torsion member  80  is inserted over the first extension  52  and abuts the first washer  180 . A bell-shaped washer or keeper  182 , having a centrally located aperture  184  and an outer diameter larger than the inside diameter of the first aperture  84  of the torsion member  80 , and preferably a diameter that equal to an outer diameter of the first end  82  of the torsion member  80 , is located on a distal end of the aperture  84  away from the first main beam  42 . A first nut  92  is inserted into a pocket or passage  186  ( FIGS. 5 and 6 ) extending into a bottom surface  185  of the first main beam  42 . The pocket  186  frictionally secures a plurality of sides of the first nut  92 , such that the first nut  92  cannot be rotated within the pocket  186 . Preferably, the pocket  186  has four internal sides  187  hexagonally aligned and adapted to abut four sides of a hexagonally-shaped nut  92 . A bolt  90  is inserted into the aperture  184  of the keeper  182 , through the aperture  56  of the first extension member  52 , and engages the first nut  92  inside the pocket  186 , thereby securing the washer  180 , the keeper  182 , and the first end  82  of the torsion member  80  to the second end  48  of the first main beam  42 . In the illustrated example, the keepers  182  provide uniform loading about the perimeter of the associated bushings  85 ,  89 , thereby reducing the possibility of clamp load loss. Further, it should be noted that the diameter of the each of the keepers  182  is closely toleranced to the diameter of the extensions  52 ,  72 , thereby reducing the amount of torsion transmitted from the beam  42 ,  62  to the bolts  90 . The second end  86  of the torsion member  80  is secured to the second end  68  of the second main beam  62  in a manner similar to as described above with regard to the first end  84  of the torsion member  80  and the first main beam  42 . Alternatively, the downwardly-opening pocket  186  is replaced by a sidewardly-opening pocket  190  ( FIG. 7 ) that extends into a forwardly-extending arrester  192 . The pocket  190  is defined by top and bottom walls  194  that abut the sides of the nut  92  when inserted into the pocket  190 . It is noted that the illustrated example of  FIG. 7  is an example of a single-piece formed beam  42   a  and extension  52   a.    
         [0028]     An alternative embodiment of the suspension assembly  10   a  ( FIG. 3 ) comprises first and second main beams  42   a ,  62   a  that include integrally molded first and second extension members  52   a ,  72   a . In the illustrated example, the main beams  42   a ,  62   a  are formed from the same material as the extension members  52   a ,  72   a , thereby allowing a thinner cross-sectional thickness for the main beams  42   a ,  62   a  while maintaining lateral compliance, and further reducing the material proximate the interface of the extension members  52   a ,  72   a  with the main beams  42   a ,  62   a . The main beams  42   a ,  62   a  with the extension members  52   a ,  72   a  are adapted to engage and couple with the torsion member  80   a  in a similar manner to that of the main beams  42 ,  62  and the torsion member  80 , as described above.  
         [0029]     Another alternative embodiment of the suspension assembly  10   b  ( FIGS. 8 and 9 ) is similar to the suspension assembly  10  illustrated in  FIG. 7 , with the most notable exception being the configuration of the pocket and associated nut. Since suspension assembly  10   b  is similar to the previously described suspension assembly  10 , similar parts appearing in  FIGS. 1A-2  and  7  and  FIG. 8 , respectively, are represented by the same, corresponding reference numeral, except for the suffix “b” in the numerals of the latter. In the illustrated example, each of the main beams  42   b  includes a horizontally-extending, cylindrically-shaped aperture  199  that receives a cylindrical rod nut  200  having a threaded aperture  202  extending orthogonally to a longitudinal axis of the rod nut  200 . Although the associated extension member  52   b  is illustrated as being integrally formed within the main beam  42   b , it is noted that these components may be separately formed. Assembly is accomplished similarly to that discussed above with the bolt  90   b  extending through the keeper  182   b , the first end  82   b  of the torsion member  80   b , and the extension  52   b , and threadably received within the threaded aperture  202  of the rod nut  200 .  
         [0030]     The present inventive vehicle suspension assembly described herein provides an air spring suspension system with increased roll and lateral shift resistance. Further, the assembly is lightweight, capable of a long operating life, and is particularly well adapted for the proposed use.  
         [0031]     In the foregoing description, it will be readily appreciated by those skilled in the art that modifications may be made to the invention without departing from the concepts disclosed herein. Such modifications are to be considered as included in the following claims, unless these claims by their language expressly state otherwise.