Patent Publication Number: US-7722064-B2

Title: Tapered joint for vehicle suspension components

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
   This application is a continuation of U.S. Ser. No. 11/117,659, filed Apr. 28, 2005, (now U.S. Pat. No. 7,475,892), which is a divisional of U.S. Ser. No. 10/406,810, filed Apr. 3, 2003 (now U.S. Pat. No. 6,945,548), which is a continuation-in-part of U.S. Ser. No. 09/793,740, filed Feb. 26, 2001 (now U.S. Pat. No. 6,851,689 (Dudding, et al.)), and hereby claims the benefit of priority of all of the aforementioned applications and patents. Additionally, the complete disclosure of U.S. Pat. No. 6,851,689 (Dudding et al.), the complete disclosure of U.S. Pat. No. 6,945,548, and the complete disclosure of U.S. Ser. No. 11/117,659, filed Apr. 28, 2005, are hereby incorporated herein by reference. 

   BACKGROUND OF THE INVENTION 
   The present invention relates generally to innovations and improvements in vehicle suspensions. More particularly, the present invention relates to a new and improved vehicle suspension that does not react significantly to torsional forces produced by high-torque drivetrain such as those utilized in heavy-duty trucks and the like, yet exhibits excellent ride and handling characteristics. 
   For several reasons, including use of higher horsepower engines and advances in engine technology, there have been increases in the torque output of heavy-duty truck engines. Such increases have magnified the problems of driveline vibration associated with trailing arm air suspensions, which are inherently torque reactive. When increased torque is applied to the axle of a truck equipped with such a torque reactive suspension, such as during acceleration, the frame of the truck rises up and away from the drive axle. This condition is known and referred to in the art as “frame rise”. 
   It has been found that driveline vibration in vehicles, particularly heavy-duty trucks, is generally proportional to the severity of frame rise and wheel hop, and vice versa. Further, it has been found according to this invention that means for and methods of preventing or minimizing frame rise will result in suppressing driveline vibration and wheel hop. 
   Various non-reactive drive axle suspensions are known in the art. The term “non-reactive” means that the suspension does not react appreciatively to torque applied to a drive axle, particularly during acceleration and deceleration (braking). 
   Various roll stable suspensions are also known in the art. The term “roll stable” means that a suspension adequately resists the tendency of a vehicle to roll when negotiating sharp turns. A suspension exhibiting that feature is said to have roll stability. 
   Various air suspensions are also known. The term “air suspension” refers to a suspension equipped with air springs or bellows for supporting a vehicle on an axle. 
   Before the present invention, the various known air suspensions have not adequately managed the mobility versus stability tradeoff. Most air suspensions that are adequately roll stable do not provide adequate mobility. Conversely, most air suspensions that provide mobility do not provide sufficient roll stability. Further, such suspensions have reduced the comfort and ride characteristics of the suspension. 
   It is also desirable for a suspension to maintain the axle inclination angle or “pinion” angle throughout the full range of axle travel. By doing this, the axle pinion angle will more closely match the drive shaft angle and by so doing minimizes driveline vibration. The parallelogram geometry created by the beam and control rod maintains the pinion angle where a trailing arm suspension does not. 
   These prior art non-torque reactive suspensions are also generally heavy, translating into reduced payload capacity in commercial vehicle applications. Such suspensions are also generally expensive to manufacture in terms of increased component parts and they require lengthy installation and assembly time, which further increases their manufacturing expense. The prior art non-torque reactive suspensions also have generally low roll stability, thereby limiting use of the vehicle to certain, limited applications. 
   In light of the foregoing, it is desirable to design a vehicle suspension that will overcome one or more of the above-identified deficiencies of conventional non-torque reactive suspensions. 
   It is further desirable to design a vehicle suspension that is non-torque reactive. 
   It is further desirable to design a vehicle suspension that is a non-torque reactive air suspension. 
   It is further desirable to design a vehicle suspension that minimizes loads into the vehicle frame and its associated cross member. 
   It is further desirable to design a non-torque reactive suspension that exhibits excellent roll stability characteristics. 
   It is further desirable to design a non-torque reactive suspension that does not compromise ride and/or articulation characteristics, while providing excellent roll stability. 
   It is further desirable to design a vehicle suspension that minimizes the number of components required to achieve its objectives. 
   It is further desirable to design a vehicle suspension that can be assembled and installed in a relatively short amount of time. 
   It is further desirable to design a vehicle suspension that is relatively light in weight, thereby translating into increased payload capacity when used in commercial vehicle applications. 
   It is further desirable to provide a rear drive axle air suspension suitable for applications requiring partial off highway operation. 
   It is further desirable to design a vehicle suspension that is rated from 20,000 lb. to 23,000 lb. ground load per axle. 
   It is further desirable to design a vehicle suspension that can be used in connection with a variety of axle configurations, including single, tandem, or tridem axle configurations. 
   It is further desirable to design a vehicle suspension that is a non-reactive suspension developed for heavy-duty vehicles with high torque engines. 
   It is further desirable to design a vehicle suspension that minimizes vibration. 
   It is further desirable to design a vehicle suspension that improves ride quality. 
   It is further desirable to design a vehicle suspension that eliminates torque reactivity. 
   It is further desirable to design a vehicle suspension that includes various unique torque rod design configurations. 
   It is further desirable to provide a vehicle suspension that has an optimized parallelogram geometry. 
   It is further desirable to design a vehicle suspension that does not induce roll generated torque into the drive axle of a vehicle. 
   It is further desirable to design a vehicle suspension that includes a machine tapered joint for the connection between the longitudinally extending main beam sections and the laterally extending crossbrace. 
   It is further desirable to design a vehicle suspension that utilizes a D-shaped bar pin bushing for attachment to a single leg of the lower axle bracket used to connect various suspension components to the clamped drive axle housing. 
   It is further desirable to design a vehicle suspension that includes an axle clamp assembly bottom pad having shock and main beam bushing mounting structure for adjustment of the axle pinion angle. 
   It is further desirable to design a vehicle suspension that utilizes frame hanger components with integrated main beam and control rod mounting features. 
   It is further desirable to design a vehicle suspension that utilizes an axle clamp assembly top pad having integrated control mounting and bump stop features. 
   It is further desirable to design a vehicle suspension that includes roll stiffness tuning capability. 
   It is further desirable to design a vehicle suspension having features that aid in the assembly of the bushing interface. 
   It is further desirable to design a vehicle suspension having a geometry that eliminates axle pinion angle change throughout the range of vertical axle travel. 
   It is further desirable to design a vehicle suspension having a geometry with links connected both above and below the axle to resist axle torsional displacements that are generated by braking and acceleration. 
   It is further desirable to design a vehicle suspension having a parallel geometry that reduces driveline vibration relative to typical trailing beam style suspensions common in the industry. 
   It is further desirable to design a vehicle suspension having a parallel geometry that reduces driveline vibration relative to typical trailing beam style suspensions common in the industry. 
   It is further desirable to design a vehicle suspension that has an alternative geometry replacing two longitudinal and one lateral control rod with a single V-rod configuration that forms the upper linkage in the parallelogram geometry of the suspension and supports lateral loads. 
   It is further desirable to design a vehicle suspension that has pivotal connections at the axle rather than rigid connections such that no torsional loads are transmitted into the axle, making the axle interface more robust than the typical rigid connection. 
   It is further desirable to design a vehicle suspension that eliminates the axle as an auxiliary roll-stabilizing component, yet obtains roll stability through various components of the suspension. 
   It is further desirable to design a vehicle suspension that prevents vehicle frame rise. 
   It is further desirable to design a vehicle suspension wherein the pivot for connecting other suspension components to the frame hanger is approximately aligned with the axle pivot. 
   It is further desirable to design an axle clamp assembly top pad having built-in axle stop features in the form of an inboard ear used for mounting a suspension system control rod. 
   It is further desirable to design an air spring mounting assembly including a unique air spring spacer component. 
   These and other benefits of the preferred forms of the invention will become apparent from the following description. It will be understood, however, that an apparatus could still appropriate the invention claimed herein without accomplishing each and every one of these benefits, including those gleaned from the following description. The appended claims, not the benefits, define the subject matter of this invention. Any and all benefits are derived from the preferred forms of the invention, not necessarily the invention in general. 
   BRIEF SUMMARY OF THE INVENTION 
   The present invention is directed to a non-torque reactive air suspension exhibiting excellent ride and handling characteristics. The suspension includes frame hangers mounted to frame rails extending longitudinally on opposite sides of a vehicle. Longitudinally extending beams are connected to the frame hangers at one end and extend parallel to the frame rails. At their other ends, the beams are joined by a crossbrace extending laterally across the vehicle centerline. In a central portion thereof, the beams have an axle pivot bore to which an axle clamp assembly is connected, the axle clamp assembly clamping a drive axle housing for the vehicle. The axle pivot bore is generally aligned with the drive axle. A control rod assembly is connected to suspension or frame components. Together with the beams, the control rod assembly forms a parallelogram configuration wherein the beams form the lower linkages of that configuration and the control rods included within the control rod assembly form the upper linkages of that configuration. 
   In a preferred aspect, the frame hangers include control rod mounting features. These features permit the incorporation of longitudinally extending control rods outboard of the vehicle frame rails. The frame hangers also preferably include features that facilitate installation and assembly of the suspension components, specifically the beams. 
   In another preferred aspect, the top pad for the axle clamp assembly includes control rod mounting features. These features also permit the incorporation of longitudinally extending control rods outboard of the vehicle frame rails. The top pad also preferably includes a bump stop. 
   In still another preferred aspect, the bottom pad for the axle clamp assembly includes a single leg having a curved surface to accommodate the curved portion of a D-shaped bar pin bushing that connects the axle clamp assembly to the beam through its axle pivot bore. This construction facilitates adjustment of axle pinion angle, as desired. The bottom pad also preferably includes shock damper mounting features. 
   In yet another preferred aspect, the connection assembly that joins the crossbrace at corresponding beam ends includes a machine taper joint and a square-like geometry, exhibiting excellent roll stability characteristic during vehicle operation. 
   In alternative embodiments, the suspension can include various control rod configurations, including a first having two longitudinally extending control rods mounted on the frame hanger and axle clamp assembly outboard of the vehicle frame rails and one laterally extending control rod mounted between the drive axle housing and one of the vehicle frame rails, a second having a V-rod configuration mounted at an apex to the drive axle housing and at each end to opposite ones of the vehicle frame rails, and a third having a single longitudinally extending control rod mounted between the drive axle housing and a frame cross member extending laterally and mounted to both vehicle frame rails and a single laterally extending control rod mounted to the drive axle housing and one of the vehicle frame rails. 

   
     BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWING 
     In the following detailed description, reference will frequently made to the following figures, in which like reference numerals refer to like components, and in which: 
       FIG. 1  is a rear perspective view of a drive axle suspension for a heavy duty truck or the like constructed in accordance with the principles of the present invention; 
       FIG. 1A  is a perspective view of a bushing used in the suspension shown in  FIG. 1 ; 
       FIG. 2  is a side elevational view of the suspension shown in  FIG. 1 ; 
       FIG. 3  is a side elevational view of one of the main beams used in the suspension shown in  FIG. 1 ; 
       FIG. 4  is an exploded perspective view illustrating the connection between the main beam shown in  FIG. 3  and the crossbrace used in the suspension shown in  FIG. 1 ; 
       FIG. 4A  is a rear perspective view of a retainer cup that can be used in the connection assembly shown in  FIG. 4 ; 
       FIG. 4B  is a side view of the retainer cup shown in  FIG. 4A ; 
       FIG. 5  is a sectional view of the main beam shown in  FIG. 3  taken along line  5 - 5 ; 
       FIG. 6  is a side elevational view of a preferred form of the axle clamp assembly used in the suspension in  FIG. 1 ; 
       FIG. 6A  is a perspective view of an alternative form of the axle clamp assembly shown in  FIG. 6 ; 
       FIG. 7  is a rear perspective view of a frame hanger assembly used in the suspension shown in  FIG. 1 ; 
       FIG. 8  is a rear perspective view of the suspension shown in  FIG. 1  having its axle clamp assembly top pad substituted for an alternative preferred form of that component; 
       FIG. 9  is a rear perspective view of the axle clamp assembly top pad included within the suspension shown in  FIG. 8 ; 
       FIG. 10  is a rear perspective view of the suspension shown in  FIG. 1  having an alternative control rod configuration; 
       FIG. 11  is a top plan view of the alternative control rod configuration used in the suspension shown in  FIG. 10 ; 
       FIG. 12  is a rear perspective view of the suspension shown in  FIG. 1  having yet another alternative control rod configuration; 
       FIG. 13  is a rear view illustrating features of the suspension shown in  FIG. 2 ; 
       FIG. 14  is a rear perspective view of another drive axle suspension for a heavy duty truck or the like constructed in accordance with the principles of the present invention; 
       FIG. 15  is a rear perspective view of yet another drive axle suspension for a heavy duty truck or the like constructed in accordance with the principles of the present invention; 
       FIG. 16  is an exploded perspective view of an axle clamp assembly and certain other associated components that may be included within a suspension constructed in accordance with the principles of the present invention; 
       FIG. 17  is an exploded perspective view of an axle stop and top pad sub-system and other associated components that may be included within a suspension constructed in accordance with the principles of the present invention; 
       FIG. 18  is an exploded perspective view of another axle stop and top pad sub-system and other associated components that may be included within a suspension constructed in accordance with the principles of the present invention; 
       FIG. 19  is an air spring mounting assembly and beam-to-crossbrace joint assembly that may be included within a suspension constructed in accordance with the principles of the present invention; 
       FIG. 20  is an elevational view of an air spring assembly shown in section; and 
       FIG. 21  is a bottom view of the air spring assembly shown in  FIG. 20 . 
   

   DETAILED DESCRIPTION OF THE INVENTION 
     FIGS. 1 and 2  illustrate components used in association with a vehicle, such as a heavy-duty truck and the like (not shown). The vehicle includes longitudinally extending frame rails  20  positioned on opposite sides of the vehicle and having a preferred C-shaped configuration. The vehicle further includes a drive axle having a housing illustrated in  FIG. 1  by reference numeral  22 . The drive axle for the vehicle extends laterally across the vehicle and is used to mount tires (not shown) driven by a vehicle engine (not shown). 
   In addition to the foregoing, the vehicle further includes a suspension generally designated by reference numeral  24 , which connects the drive axle housing  22  to frame rails  20 - 20  positioned on opposite sides of the vehicle. 
   As will be appreciated, with respect to suspension  24 , the majority of the components positioned on one side of the vehicle will have correspondingly similar components positioned on the other side. Accordingly, in this description, when reference is made to a particular suspension component, it will be understood that a similar component is present on the opposite side of the vehicle, unless otherwise apparent. 
   Suspension  24  includes a plurality of components including frame hangers  26  mounted on opposite sides of the vehicle to frame rails  20 - 20 . Suspension  24  further includes longitudinally extending main beams  28 - 28  connected at one end to a frame hanger  26  through a bushing  30  (see  FIG. 1A ) and an eccentric washer or member  31 , which allows axle adjustment for the suspension. At the other end, beams  28 - 28  are connected to a laterally extending crossbrace  32  by way of a beam-to-brace connection assembly  34 . As shown, a single crossbrace is utilized for each axle using the suspension  24  illustrated in  FIG. 1 . As such, crossbrace  32  extends laterally across the vehicle to connect with the rearward ends of the beams  28 - 28  positioned on opposite sides of the vehicle. 
   Crossbrace  32  forms a semi-torsion bar which lifts and rotates while resisting moments about all three axes of a Cartesian coordinate system. Crossbrace  32  is the primary component contributing to roll stability for suspension  24 . 
   A secondary component for the roll stability of suspension  24  is the bushing  30  that is used to connect beam  28  with frame hanger  26 . Bushing  30 , illustrated in  FIG. 1A , preferably is a sleeveless bushing and has an outer rim surface  33  on each end thereof trapped and compressed between the beam and the inner walls of the depending panels of the frame hanger when the bushing is installed within the bore positioned at the forward end of beam  28  and beam  28  is connected to frame hanger  26 . As such, this outer surface  33  of bushing  30  reacts against vehicle roll as the vehicle negotiates sharp turns and the trapped conical rate of the bushing provides additional roll stability. 
   Between their ends, beams  28 - 28  include an axle pivot bore  36  (see  FIG. 3 ), which permits an axle clamp assembly generally designated by reference numeral  38  to connect the drive axle housing  22  to each beam  28  for pivotal movement. The axle pivot bore  36  is positioned at the center of the drive axle. The combination of beam and control rod linkages to the axle make the suspension non-reactive. Details of the axle clamp assembly  38  are set forth in further detail in the description regarding other figures of the drawing. 
   Further shown in  FIGS. 1 and 2  is a longitudinally extending control or torque rod  40  that is connected between frame hanger  26  and a component part of axle clamp assembly  38 . As such, two longitudinal torque rods  40 - 40  are included within suspension  24 , each positioned on an opposite side of the vehicle. Together, torque rods  40  and beams  28  form a parallelogram geometry that contributes to the desired characteristics exhibited by suspension  24 . The optimized geometry distributes loads between the torque rods  40  and beams  28  so that they are shared. The load distribution, handling characteristics and roll stability of suspension  24  can be tuned by varying the geometry thereof. 
   Similarly, a laterally extending control or torque rod  42  is included within suspension  24  and connected between drive axle housing  22  and frame rail  10  on one side of the vehicle. Laterally extending torque rod  42  extends in a direction generally transverse to the direction in which longitudinally extending torque rods  40 - 40  extend. Accordingly, laterally extending torque rod  42  can also be referred to as a transverse torque rod. 
   An axle housing control rod mounting bracket  44  is mounted to drive axle housing  22  in order to permit the laterally extending torque rod  42  to connect to the drive axle housing. Similarly, a frame rail control rod mounting bracket  46  is mounted to frame rail  10  on one side of the vehicle to permit laterally extending torque rod  42  to connect to the frame rail on which it mounts. 
   Suspension  24  further includes a shock damper  48  connected at its upper end to an upper shock bracket  50  mounted to frame rail  20  and at its lower end to the axle clamp assembly  38 , as discussed in further detail in the description regarding other figures of the drawing. Suspension  24  further includes air springs  52 - 52  connected at their respective top ends to an air spring mounting bracket  54  that is mounted to frame rail  20 . Air springs  52  are positioned on crossbrace  32  in a manner known in the art such as by being seated on a conventional, suitable air spring mounting pad (not shown). 
     FIG. 2  and  FIG. 13  also illustrate an outboard bump stop  55  mounted on frame rail  20 . As will be understood by those skilled in the art, in certain applications, air will be exhausted from the suspension to ride on bump stops. For instance, this is done to increase vehicle stability during events such as tipping a dump body to unload. The top pad  78  will strike bump stop  55  during jounce and the vertical load will pass through the top pad directly into the clamped drive axle. Top pad  178  of  FIG. 9  could also be used for this purpose. 
     FIG. 3 . illustrates one of the longitudinally extending beams  28  used in the suspension  24  depicted in the  FIG. 1 . As shown, beam  28  includes a bore  56  positioned at one end thereof in order to permit installation of bushing  30  ( FIG. 1A ) and attachment of beam  28  to frame hanger  26  ( FIG. 1 ). From that end, beam  28  extends downwardly at a relatively continuous angle towards a point  58  to define a section  60  of the beam. From point  58 , beam  28  curves upwards towards a direction where it travels along a relatively straight and horizontally extending path to define a section  61  of the beam. Beam  28  obtains the horizontally extending path at or near the axle pivot bore  36  located in a central, rearward portion of the beam. From axle pivot bore  36 , beam  28  extends generally horizontally to an open, square-like end  62  designed to receive and permit connection with the crossbrace  32  depicted in  FIG. 1 . 
     FIGS. 4 and 5  illustrate the connection assembly  34  used to connect the end of each longitudinally extending beam  28  with an associated end of crossbrace  32  to establish a joint between same. During operation of suspension  24 , it will be appreciated that this joint will be subjected to high bending moments about all three axes of a three dimensional Cartesian coordinate system. 
   Connection assembly  34  preferably includes a plug component  64  having a bore  66 , a retainer plate  68  also having a bore  70 , and a fastener  72 . Plug component  64  is secured within the interior of hollow crossbrace  32 . It will be appreciated that in an alternative arrangement plug component  64  could be integrally formed with crossbrace  32  during the manufacturing process. 
   Retainer plate  68  is brought into contact with the outboard, square-like surface of end  62  of beam  28  to axially align bores  66 ,  70 . Once aligned, fastener  72  is inserted through bores  66 ,  70  and the joint is formed between beam  28  and crossbrace  32  by drawing the crossbrace end towards the beam end. It will be appreciated that bore  66  can be tapped in order to facilitate formation of the joint between beam  28  and crossbrace  32 . Other fastening arrangements can also be used. 
   Still referring to  FIGS. 4 and 5 , crossbrace  32  includes inwardly tapered surfaces  74  defining the walls at each end. Similarly, the square-like end  62  of beam  28  has a tapered surface  76  defining each of its inner walls. Preferably, the tapered surfaces  74 ,  76  form a six degree angle. Inwardly tapered surfaces  74  of crossbrace  32  and inwardly tapered surfaces  76  of beam  28  are designed to allow corresponding ones of the surfaces to mate and cause frictional contact during vehicle operation. This frictional contact and squared geometry of the joint resists the torsional loads about the lateral axis of crossbrace  32 . This characteristic provides exceptional roll stability for suspension  24 .  FIG. 5  does not illustrate the air spring mounts positioned in close proximity to the ends of crossbrace  32 . However, it will be appreciated that such mounts are positioned at those locations. 
     FIGS. 4A and 4B  illustrate a retainer cap  400  used in lieu of the retainer plate  68  shown in  FIGS. 4 and 5 . Retainer cap  400  is a casting having a cavity  402  that allows the fastener bolt head to be recessed, which provides increased tire clearance. Additionally, the retainer cap  400  includes bumps  404  positioned on the inboard side in each of its four corners to engage the corresponding corner of beam  28  and properly index the cap, while preventing it from rotating. 
     FIG. 6  illustrates axle clamp assembly  38  having a top pad  78  and a bottom pad  80 . Top pad  78  includes two projecting ears  82  having bores  84  extending through them. As shown in  FIG. 1 , longitudinally extending torque rod  40  can connect to axle clamp assembly  38 , and particularly to top pad  78 , by use of this structure. In that regard, a through bolt or the like can be inserted through axially aligned bores  84  to permit connection with longitudinally extending torque rod  40 . In a conventional arrangement, top pad  78  includes grooved surfaces (not shown) designed to receive U-bolts  85  and permit clamping of the drive axle housing. U-bolts  85  are preferably three-quarter inch. 
     FIG. 6A  illustrates an axle clamp assembly having a top pad  278  that includes the control rod mounting feature, described above. Top pad  278  also includes a bump stop  500  positioned inboard that will hit the underside of the frame rail during jounce and pass vertical load directly into the drive axle housing. As shown, bump stop  500  is integrated with top pad  278 , which desirably reduces the number of suspension component parts. 
   Referring back to  FIG. 6 , bottom pad  80  includes a lower shock bracket  86  integrally formed therewith. Lower shock bracket  86  permits attachment of the lower end of a shock damper such as shock damper  48  illustrated in  FIG. 1 . As such, the shock damper can be connected between axle clamp assembly  38  and the vehicle frame rail. As shown, bores  87  are machined or cast into bottom pad  80  to allow U-bolts  85  to clamp the vehicle drive axle housing. Fasteners  88  are threaded onto the ends of U-bolts  85  to clamp the axle housing between the top pad  78  and bottom pad  80  of axle clamp assembly  38 . 
   Bottom pad  80  is pivotally connected to longitudinally extending beam  28  by a D-shaped bar pin bushing  90 , which is received within axle pivot bore  36 . Bottom pad  80  includes a lower portion  92  defining a single leg and having a curved surface  94  that receives the curved portion of D-shaped bar pin bushing  90 . Lower portion  92  also has a bore machined through it that is brought into registration with the bore machined into D-shaped bar pin bushing  90 . Fastener assembly  96  includes a rod-like element that extends through the bore machined through lower portion  92  of bottom pad  80  and the bore machined through D-shaped bar pin bushing  90 . Fastener assembly  96  is then fastened to connect the clamped drive axle housing to longitudinally extending beam  28 , and bear against the flat surface of D-shaped bar pin bushing  90 . Through this arrangement, the axle pinion angle can be readily adjusted. 
     FIG. 7  illustrates a frame hanger  26  preferably used in the suspension  24  illustrated in  FIG. 1 . As shown, frame hanger  26  preferably includes mounting bores  98 , which permit the frame hanger to be mounted to a vehicle frame rail. Frame hanger  26  further includes a control rod mounting flange  100  having bores  102  machined through it to permit connection with a longitudinally extending torque rod  40  by use of a bar pin or the like. Accordingly, frame hanger  26  includes control rod mounting features integrated therewith, which provides a natural path for longitudinal loads from the axle to the frame. 
   Referring still to  FIG. 7 , another unique aspect of frame hanger  26  is structure that facilitates installation and connection of the bushing  30  ( FIG. 1A ) used to connect an end of longitudinally extending beam  28  to the frame hanger. In that regard, frame hanger  26  includes two depending panels  104 ,  106  each having a bore  108 ,  110  machined through it. An inwardly projecting surface  112  is disposed around the perimeter of bore  110  of depending panel  106 . In similar fashion, an inwardly projecting surface (not shown) is disposed around the perimeter of bore  108  of depending panel  104 . An inwardly tapering surface  114  extends from the inner wall of depending panel  106  to inwardly projecting surface  112 . Similarly, an inwardly tapering surface (not shown) extends from the inner wall of depending panel  104  to the inwardly projecting surface that is disposed about the perimeter of bore  108 . As will be appreciated by those skilled in the art, this construction greatly facilitates assembly of the longitudinally extending beam  28  to frame hanger  26  by allowing the bushing to be positioned in registration with bores  108 ,  110  more readily. 
   Ideally, bores  108 ,  110  are aligned vertically with axle  22  to provide optimum performance of suspension  24 . As hanger  26  hangs lower, however, it is greater in weight, provides less clearance, and requires more expense to manufacture. In any event, the characteristics of suspension  24  can be tuned by varying the position of the main beam pivot vis-a-vis the axle pivot. 
   To assemble the components illustrated in  FIGS. 1 and 2 , frame hangers  26 , frame rail control rod mounting brackets  46  and upper shock damper mounting brackets  50  are mounted to frame rails  20  to form a frame subassembly. The axle clamp assembly  38  is then clamped to drive axle housing  22 , while beams  28  are connected to crossbrace  32  and connected to the axle clamp assembly by D-shaped bar pin bushing  90 . The longitudinally extending control rods  40  are connected to the top pads  78  for each axle clamp assembly  38 , and the laterally extending control rod  42  is connected to the axle housing control rod mounting bracket  44  mounted on drive axle housing  22  to form an axle subassembly. Thereafter, the axle subassembly is installed into the frame subassembly. Finally, the eccentric washer or member  31  is rotated clockwise or counter-clockwise to move the drive axle forward or rearward, as desired. Further, drop in shims (not shown) can be added at the longitudinal torque rod and frame hanger interface, as desired. 
     FIG. 8  also illustrates a vehicle suspension having a geometry identical to that shown in  FIG. 1 . In the suspension shown in  FIG. 8 , the axle clamp assembly includes a top pad  178  having a different construction from that depicted in  FIGS. 1 ,  2  and  6 . 
   Referring to  FIG. 9 , top pad  178  includes an axle clamp base portion  180  and a control rod mounting portion generally designated by reference numeral  182 . Control rod mounting portion  182  includes two ear-like sidewalls  184 ,  186  and a curved top wall or dome surface  188 , which can serve as a bearing surface that strikes a bump stop mounted on the vehicle frame rail. Openings exist between sidewalls  184 ,  186  at opposite ends of the top pad to permit entry of a control rod. 
   Sidewall  184  includes a bore  190  machined or cast through it. Similarly, sidewall  186  includes a bore  192  machined or cast through it. Bores  190 ,  192  are in registration such that a pin can extend between them and through a bore positioned at one end of a longitudinally extending control rod such as control rod  40  depicted in  FIG. 8 . Accordingly, similar to the top pad  78  shown in  FIG. 6 , top pad  178  has control rod mounting features integrated therewith. As will be appreciated, top pad  178  might be more structurally sound, but top pad  78  is lighter in weight because it ordinarily would require less material. 
     FIG. 10  illustrates a suspension generally designated  200  that utilizes a V-shaped control rod configuration defined by a V-shaped control rod assembly generally designated  202 . In that regard, frame hanger  226  and top pad  278  can be conventional in design, and need not have control rod mounting features associated and integrated therewith. V-shaped control rod assembly  202  connects to frame rails  220  by way of frame brackets  204  mounted thereon, and further connects with drive axle housing  222  by way of a bracket  206  mounted on the housing. It will be appreciated by those skilled in the art that V-shaped control rod assembly  202  reacts to both lateral and longitudinal forces produced during vehicle operation, and that it provides the upper links for the preferred parallelogram geometry used for the roll stable, non-torque reactive vehicle suspension of the present invention. 
     FIG. 11  illustrates V-shaped control rod assembly  202 . Assembly  202  includes an apex component  208  having a bushing  210  for connection with bracket  206  on the drive axle housing  222 . Assembly  202  further includes control rods  212 ,  214  fastened to apex component  208  by fasteners  216 . Control rods  212 ,  214  include bushings  218  for attachment to frame brackets  204  mounted on opposing frame rails  222  that extend longitudinally along opposite sides of the vehicle. Apex component  208  includes two recessed portions  224  defining channels that permit connection with control rods  212 ,  214  and direct them along their desired path, orientating them towards frame rails  220 . 
     FIG. 12  illustrates a suspension generally designated  300  that utilizes a two rod control rod configuration. In that regard, a longitudinally extending control rod  302  connects to a cross member  304  of frame rails  306  by way of a frame bracket  308  mounted to the cross member, and further connects with drive axle housing  310  by way of bracket (not shown) mounted on the housing. This connection is not shown to facilitate illustration of this control rod configuration. Similarly, a laterally extending control rod  314  connects to one frame rail  306  by way of a frame bracket  316  mounted thereon, and further connects with drive axle housing  310  by way of a bracket  318  mounted on the housing. It will be appreciated by those skilled in the art that control rod  302  reacts to longitudinal torque forces produced during vehicle operation, and control rod  314  reacts to lateral torque forces produced during vehicle operation. Together, control rods  302 ,  314  provide the upper links for the preferred parallelogram geometry used for the roll stable, non-torque reactive vehicle suspension of the present invention. 
     FIG. 14  illustrates components used in association with a vehicle, such as a heavy-duty truck and the like (not shown). The vehicle includes two opposing longitudinally extending frame rails  400  positioned on opposite sides of the vehicle and having a preferred C-shaped configuration. The illustrated vehicle further includes tandem drive axles with a conventional housing (not shown). Those skilled in the art will appreciate that each drive axle extends laterally across the vehicle and is used to mount brakes, wheels and tires (not shown) driven by a vehicle engine (not shown). 
   In addition to the foregoing, the vehicle further includes a suspension generally designated by reference numeral  402 , which connects the drive axle housings to frame rails  400  positioned on opposite sides of the vehicle. 
   As will be appreciated, with respect to suspension  402 , the majority of the components positioned on one side of the vehicle will have correspondingly similar components positioned on the other side. Accordingly, in this description, when reference is made to a particular suspension component, it will be understood that a similar component is present on the opposite side of the vehicle, unless otherwise apparent. 
   Suspension  402  includes a plurality of components including frame hangers  404  mounted on opposite sides of the vehicle to frame rails  400 . Suspension  402  further includes longitudinally extending main beams  406  connected at one end to a frame hanger  404 . At the other end, beams  406  are connected to a laterally extending crossbrace  408  by way of a beam-to-brace connection assembly  410 . As shown, a single crossbrace  408  is utilized for each axle using the suspension  402  illustrated in  FIG. 14 . As such, crossbrace  408  extends laterally across the vehicle to connect with the rearward ends of beams  406  positioned on opposite sides of the vehicle. Those skilled in the art will appreciate that, alternatively, crossbrace  408  could connect between oppositely positioned beams  406  intermediate their ends. 
   Crossbrace  408  forms a semi-torsion bar which lifts and rotates while resisting moments about all three axes of a Cartesian coordinate system. Crossbrace  408  is the primary component contributing to roll stability for suspension  402 . 
   A secondary component for the roll stability of suspension  402  is the bushing (not shown) that is used to connect each when beam  406  with a frame hanger  404 . This bushing is preferably a sleeveless bushing and has an outer rim surface on each end thereof trapped and compressed between the beam and the inner walls of the depending panels of the frame hanger when the bushing is installed within the bore positioned at the forward end of beam  406  and when beam  406  is connected to frame hanger  404 . As such, this outer surface of the bushing reacts against vehicle roll as the vehicle negotiates sharp turns and the trapped conical rate of the bushing provides additional roll stability. 
   Between their ends, beams  406  include an axle pivot bore (not shown), which permits an axle clamp assembly generally designated by reference numeral  412  to connect the drive axle housing to each beam  406  for pivotal movement. The axis of the axle pivot bore is parallel to the centerline of the drive axle. The combination of beam and control rod linkages to the axle react brake and drive torques, which characterizes the suspension as non-reactive. Details of the axle clamp assembly  412  are set forth in further detail in the description regarding other figures of the drawing. 
   Further shown in  FIG. 14  is a longitudinally extending control or torque rod  414  that is connected between frame hanger  404  and a component part of axle clamp assembly  412 . Together, torque rods  414  and beams  406  form a parallelogram geometry that contributes to one of the desired characteristics exhibited by suspension  402 . The optimized geometry distributes loads between the torque rods  414  and beams  406  so that they are shared. The load distribution, handling characteristics and roll stability of suspension  402  can be tuned by varying the geometry thereof. 
   Similarly, laterally extending control or torque rods  416  are included within suspension  402  and are connected between the drive axle housings and frame rails  400 . Laterally extending torque rods  416  extend in a direction generally transverse to the direction in which longitudinally extending torque rods  414  extend. Accordingly, laterally extending torque rods  416  can also be referred to as a transverse torque rods. 
   An axle housing control rod mounting bracket (not shown) is mounted to the drive axle housing in order to permit a laterally extending torque rod  416  to connect to the drive axle housing. Similarly, a frame rail control rod mounting bracket  418  is mounted to frame rail  400  on one side of the vehicle to permit a laterally extending torque rod  416  to connect to the frame rail on which it mounts. 
   Suspension  402  further includes a shock damper  420  connected at its upper end to an upper shock bracket  422  mounted to frame rail  400  and at its lower end to the axle clamp assembly  412 . Suspension  402  further includes air springs  424  connected at their respective top ends to an air spring mounting bracket  426  that is mounted to frame rail  400 . Air springs  424  are mounted on crossbrace  408  by way of an air spring mounting assembly  428 , which is described with reference to  FIG. 18 . 
     FIG. 14  also illustrates outboard axle stops  430  mounted on frame rails  400 . As will be understood by those skilled in the art, in certain applications, air will be exhausted from the suspension to ride on the axle stops. For instance, this is done to increase vehicle stability during events such as tipping a dump body to unload. The top pad component of the axle clamp assembly  412  can strike bump stop  430  during jounce and the vertical load will pass through the top pad directly into the clamped drive axle. 
     FIG. 15  illustrates another tandem drive axle suspension generally designated  500 . Suspension  500  is used in those situations where it is desired to have a vehicle construction wherein the distance between the drive axles and vehicle frame is relatively large. These are typically vehicles that require additional ground clearance or packaging for drivelines. Applications include but are not limited to front discharge mixers, mobile cranes, forestry vehicles, and fire/rescue vehicles. 
   Suspension  500  is, in large part, similar to suspension  400  shown in  FIG. 14 . With respect to suspension  500 , however, it includes different frame hangers  502  from those shown in  FIG. 14 . Besides hanging longer, as is the case with many of the components in suspension  500 , frame hangers  502  includes a fore-and-aft extending slot that enables its associated longitudinal control rod to be connected at horizontally differing positions with respect to the frame hanger. As a result, the orientation of each longitudinal control rod can be adapted to suit the desired characteristics of the suspension, and the suspension can be tuned appropriately. 
   Each suspension  500  illustrated in  FIG. 15  includes an axle stop  504   a  and an axle stop  504   b  that are different from the corresponding axle stops illustrated in  FIG. 14 . Each axle stop  504   a  includes a C-shaped portion having a base portion with bores that enable the axle stop to be mounted to its associated frame rail. Each axle stop  504   a  also includes a reinforcement gusset, as shown. Each axle stop  504   a  further includes a bottom plate that serves as an axle stopping surface, or top pad striking surface, to limit axle travel. 
   With respect to axle stops  504   b , they are solid with a bottom plate that serves as an axle stopping surface, or top pad striking surface, to limit axle travel. Axle stops  504   b  also serve as mounting brackets for the laterally extending control rods in suspension  500 . In that regard, the laterally extending control rods extend underneath the frame rails. 
   In addition to the foregoing, other components included within suspension  500  illustrated in  FIG. 15  are different from their corresponding components included within the suspension illustrated in  FIG. 14 . 
     FIG. 16  illustrates a representative drive axle housing  600 , axle clamp assembly  412 , beam  406  and a D-shaped bar pin bushing  602 . As shown, axle clamp assembly  412  includes a top pad component  604 , a axle hanger  606 , two laterally spaced, downwardly projecting U-bolts  608  and sets of washer and nut fasteners that are applied to the threaded ends of the U-bolts. Top pad component  604  includes an inboard ear  610  and an outboard ear  612 . Inboard ear has a relatively thick construction and includes a flattened top surface. Outboard ear  612  tapers to a rounded peak and is relatively thin as compared to inboard ear  610 . Both ears  610 ,  612  include bores that are aligned to permit mounting of a longitudinal control rod  414  (see  FIG. 17 ). Top pad component  604  also includes two grooved portions that enable the longitudinally extending base portions of U-bolts  608  to sit therein. 
   The connection of axle hanger  606  with beam  406  through D-shaped bar pin bushing  602  is described elsewhere in this specification. 
     FIG. 17  illustrates one of the C-shaped vehicle frame rails  400 , an axle stop  430 , a longitudinally extending control rod  414 , top pad component  604 , control rod mounting fastener assembly  614 , and a representative drive axle housing  600 . The axle stop  430  is mounted to vehicle frame rail  402 . The axle stop  430  illustrated in  FIG. 17  is a casting. Axle stop  430  includes bores that enable it to be mounted to frame rail  400  and further includes a flattened bottom striking surface for contact with the inboard ear  610  of top pad component  604 . 
   Longitudinal control rod  414  is mounted between inboard ear  610  and outboard ear  612  of top pad component  604  by way of the control rod mounting fastener assembly  614 . Top pad component  604  is seated on drive axle housing  600  and secured thereto by U-bolts  608  (see  FIG. 16 ). 
   When air is exhausted from the suspension in order to ride the axle stops, the relatively thick inboard ear  610  will strike the bottom surface of axle/bump stop  430  during jounce and the vertical load will pass through the top pad directly into the clamped drive axle  600 . As a result, the axle jounce travel is limited. The amount of axle travel during jounce can be tuned by changing the vertical position of the frame mounted axle stop  430 , or by changing the axle stop geometry. A recess (not shown) is preferably included on the inboard side of inboard ear  610 . The bolt head and inboard washer preferably included within fastener assembly  614  is nested into this recess to increase clearance between the bolt head or fastener assembly  614  and the frame rail  400  in a jounce condition. 
     FIG. 18  illustrates these same components, but utilizes an axle stop  630  that is a fabrication in lieu of a casting. Other than the foregoing, the description in reference to  FIG. 17  applies to the components illustrated in  FIG. 18 . 
     FIG. 19  illustrates an air spring  424 , a crossbrace  408  and an air spring mounting assembly. Air spring mounting assembly includes a spacer  700 , a bracket  702  and fasteners. The spacer  700  is a component not included within conventional air spring assemblies. Spacer  700  elevates the air spring piston  703  (see also  FIG. 20 ) and mounts it directly to crossbrace  408 . Spacer  700  is preferably made from injection-molded glass reinforced plastic in accordance with conventional manufacturing techniques. Spacer  700  could also be made by other manufacturing techniques. Additionally, spacer  700  could be made from different materials, such as die cast aluminum or cast iron, for example. Spacer  700  is preferably fastened to the air spring piston base by a single center-mounted fastener (see  FIG. 20 ). Alternatively, spacer  700  could be glued to the air spring piston  703 . Still further, spacer  700  and the air spring piston  703  could be molded as a single component. 
   This air spring assembly, which includes spacer  700 , and is illustrated in  FIG. 20 , is mounted to crossbrace  408  by lower air spring bracket  702  that is shaped as a hat section with a longitudinally extending base, vertically upwardly extending legs that extend from the ends of the base, and longitudinally extending flanges that extend from the ends of the upward legs. The flanges have bores to enable the bracket  702  to be secured to spacer  700  by the studs molded into the air spring spacer (see also  FIG. 21 ). 
   Spacer  700  includes a winged portion  704  that preferably uses a dovetail joint at its end to engage the end cap or retainer plate  68  of the beam-to-crossbrace joint assembly. Those skilled in the art will recognize that the dovetail joint could embody an alternative design. This feature simplifies air spring installation by providing a mechanism to permit the air spring to be located at its precise lateral position on the crossbrace. In addition, this feature provides lateral support for the air spring by prohibiting it from slipping laterally inboard. 
   In addition, spacer  700  has a stop  705  (see  FIGS. 20 and 21 ) positioned on the underside of the spacer and forming the edge of the base portion of the spacer extending downward from the boundary between the spacer base portion and spacer winged portion  704 . Stop  705  bears against the inboard edge of the beam to provide lateral support for the air spring by prohibiting it from slipping laterally outboard. 
   While this invention has been described with reference to certain illustrative embodiments, it will be understood that this description shall not be construed in a limiting sense. Rather, various changes and modifications can be made to the illustrative embodiments without departing from the true spirit and scope of the invention, as defined by the following claims. Furthermore, it will be appreciated that any such changes and modifications will be recognized by those skilled in the art as an equivalent to one or more elements of the following claims, and shall be covered by such claims to the fullest extent permitted by law.