Abstract:
An axle housing ( 110 ) for clamping with a clamp assembly ( 118, 218 ) to a spring ( 16, 216 ) of a suspension system ( 14 ) of a vehicle, the clamp assembly having at least two U-bolts ( 120, 220 ) each having a curved portion ( 136, 236 ) and two generally linear legs ( 128, 228 ) extending therefrom, and a clamping plate ( 122, 222 ) for receiving and attaching the legs of the U-bolts to form an enclosure that clamps the axle housing ( 110 ) to the spring ( 16, 216 ), the housing having a generally oval shape in cross section. The axle housing ( 110 ) has a generally planar fore side ( 132 ), a generally planar aft side ( 134 ), a generally rounded top surface ( 144 ) and a generally rounded bottom surface ( 146 ), wherein at least one of the top surface and the bottom surface are sized and arranged to mate flushly with the curved portion ( 136 ) of the U-bolts ( 120 ).

Description:
BACKGROUND 
     Embodiments disclosed herein relate generally to suspension systems of vehicles. More particularly, the embodiments relate to clamp assemblies for attaching axle housings to suspension systems of vehicles. 
     Suspension systems provide comfort to the occupants of vehicles. The basic function of the suspension system is to provide a flexible support for the vehicle so that the occupants are isolated from a non-planar or imperfect road surface while stabilizing the vehicle under various operating conditions. 
     Axle housings are suspended from vehicle frames with clamp assemblies. The clamp assemblies clamp the axle housing to a spring of the suspension system. In a leaf spring suspension system, the spring is attached at its two ends to the vehicle frame with hanger brackets, and a center portion of the spring is attached to the clamp assembly. The clamp assembly includes two U-bolts which confine the axle housing with a clamping plate, and clamp the axle housing against the spring. 
     Axle housings are typically cylindrical or rectangular/square in cross-section. To prevent relative rotation of the axle housing with respect to the clamp assembly, especially during acceleration and braking, rectangular/square axle housings are used. The rectangular/square axle housings are disposed in a flush arrangement between the linear legs of the U-bolts. 
     In this configuration, the curved portion of the U-bolts encircle the flat, top surface of the spring. However, flush contact between the curved portion of the metal U-bolt and another component maintains the shape of the U-bolt and provides sufficient clamping force. Axle saddles are used for this purpose. The axle saddle is disposed between the curved portion of the U-bolt and the spring. The axle saddle has a curved surface that abuts the curved U-bolt, and a flat surface that abuts the flat surface of the spring. Often, more than one axle saddle is used to provide flush contact between the U-bolt, the spring and the axle housing. 
     SUMMARY 
     An axle housing for clamping with a clamp assembly to a spring of a suspension system of a vehicle, the clamp assembly having at least two U-bolts each having a curved portion and two generally linear legs extending therefrom, and a clamping plate for receiving and attaching the legs of the U-bolts to form an enclosure that clamps the axle housing to the spring, the housing having a generally oval shape in cross section. The axle housing has a generally planar fore side, a generally planar aft side, a generally rounded top surface and a generally rounded bottom surface, wherein at least one of the top surface and the bottom surface are sized and arranged to mate flushly with the curved portion of the U-bolts. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a perspective view of a prior art axle housing mounted on frame with a leaf spring, U-bolt and axle saddle. 
         FIG. 2  is an exploded perspective view of an oval axle housing mounted on the frame with a leaf spring and a U-bolt. 
         FIG. 3  is a section view of the axle housing and axle shaft taken along line A-A of  FIG. 2 . 
         FIG. 4  is an exploded perspective view of the oval axle housing mounted on the frame with an air spring. 
         FIG. 5  is a section view of the axle housing and axle shaft taken along line A-A of  FIG. 4 . 
     
    
    
     DETAILED DESCRIPTION 
     Referring to  FIG. 1 , an axle housing  10  is generally square or rectangular shaped, and is mounted on a vehicle frame rail  12  through a suspension system, indicated generally at  14 . Specifically, the axle housing  10  is supported on a leaf spring  16  with a clamp assembly  18  that includes two U-bolts  20 , a clamping plate  22 , an axle shim  24  and an axle saddle  26 . 
     The two U-bolts  20  are spaced and in a parallel arrangement encircling the leaf spring  16 . Two legs  28  of each U-bolt  20  are received by and fastened to the clamping plate  22 , and the axle housing  10  is mounted between the two sets of legs  28 . A stop  30  positively locates the axle housing  10  in the middle of the clamping plate  22  and between the legs  28 . The legs  28  of the U-bolts  20  are generally linear, but do not abut the planar fore side  32  and aft side  34  of the square axle housing  10 . The legs  28  do not prevent rotation of the axle housing  10  with respect to the clamp assembly  18 . In this configuration, the axle housing  10  is clamped between the clamping plate  22  and the leaf spring  16 , which prevents rotation. 
     At a curved portion  36  of each U-bolt  20 , the axle saddle  26  is disposed between the U-bolt  20  and a top, flat surface  38  of the leaf spring  16 . The axle saddle  26  has a generally flat side  40  to abut the leaf spring  16 , and a generally curved side  42  to approximate the curvature of the U-bolt  20 . The axle saddle  26  is used to provide flush contact with the U-bolt  20  and the leaf spring  16 , which in turn maintains the shape and consistency of the U-bolt and provides a better clamping force. 
     Referring now to  FIG. 2  and  FIG. 3 , an axle housing is indicated at  110 . The axle housing  110  has a generally oval-shape in cross-section, and is clamped to the leaf spring  16  of a suspension system  14  with a clamp assembly  118 . The clamp assembly  118  includes two U-bolts  120  in a spaced and parallel arrangement, a clamping plate  122  mounted on a top surface  38  of the spring  16 , and an axle saddle  126  on the opposite side of the spring from the clamping plate. Suspension hangers  100  attach the leaf spring  16  to the frame rail  12  at the ends of the spring. Together with the clamping plate  122 , the U-bolts  120  attach the axle housing  110  to the leaf spring  16 . 
     Two legs  128  of each U-bolt  120  are received by and fastened to the clamping plate  122 , such as with fasteners. The axle housing  110  is mounted between the two legs of each U-bolt. When the U-bolt  120  is attached to the clamping plate  122 , a closed U-shape enclosure is formed around the axle housing  110 , and in the direction transverse to the axle housing. Each of the legs  128  of the U-bolt  120  are generally linear, one of the two legs abutting a planar fore side  132  of the axle housing  110 , and the second of the two legs abutting a planar aft side  134  of the axle housing  110 . In this arrangement, the axle housing is prevented from rotation with respect to the U-bolts  120 . 
     A top surface  144  of the axle housing  110  and a bottom surface  146  of the axle housing are each rounded to approximate the curvature of the U-bolt  120 . In other words, the outer radius of the top surface  144  and the bottom surface  146  is generally the same or slightly smaller than the inner radius of the curved portion  136  of the U-bolt  120  such that the axle housing mates flushly with or is cradled by the curved portion of the U-bolt. Further, the outer radius of the top surface  144  is generally the same as the outer radius of the bottom surface  146 . 
     The axle housing  110  is clamped between the U-bolt  120  and the axle saddle  126 , which has a generally flat side  140  to abut the leaf spring  16  and a generally curved side  142  to approximate the curvature of the top surface  144  of the axle housing. The outer radius of the top surface  144  of the axle housing  110  and the bottom surface  146  of the axle housing  110  is generally the same or slightly smaller than the inner radius of the curved side  142  of the axle saddle  126 . 
     As compared to the orientation in  FIG. 1 , the U-bolt  120  of the clamp assembly  118  of  FIG. 2  is inverted. The inversion of the U-bolt  120  provides for easier installation on the vehicle. 
     If a square or rectangular axle housing were used with the clamp assembly  118  of  FIG. 2 , a second axle saddle would be needed to provide flush contact at a curved portion  136  of the U-bolt  120  with the bottom surface  146  of the axle housing. However, with the oval axle housing  110 , no second axle saddle is needed. Further, no shim is needed to clamp the oval axle housing  110  to the frame rail  12 . Thus, the clamp assembly  118  of  FIG. 2  provides a reduction in component parts. Additionally, the oval axle housing  110  facilitates a better fit at the interface between the axle housing and the U-bolt  120 , which can result in a reduction of U-bolt stretch. Less stretch in the U-bolt  120  can result in decreased problems with all the clamping components. 
     The oval axle housing  110  is formed in two parts around an axle shaft  148 . A first portion  150  is welded to a second portion  152  with a flush weld  154  at the fore and aft surfaces  132 ,  134  of the axle housing  110  so as not to interfere with the flush contact between the axle housing and the legs  128  of the U-bolt  120 . The first portion  150  and the second portion  152  are symmetrical components that are generally centered about the axle shaft  148 . It is contemplated that other methods of attachment of the first and second portions  150 ,  152  can be used, and alternatively, an integrally formed housing can be used. 
     Referring now to  FIG. 4  and  FIG. 5 , the oval axle housing  110  is clamped on to an air spring assembly  216  of a suspension system  214  with a second embodiment of clamp assembly  218 , which includes two U-bolts  220 , a clamping plate  222  and an axle saddle  226 . As with the first embodiment of clamp assembly  118  in  FIG. 2 , the oval axle housing  110  is welded with a flush weld  154  so as to provide a planar fore side  132  and a planar aft side  134  of the axle housing. 
     In the clamp assembly  218  of  FIG. 4 , the U-bolts  220  are not inverted as in the clamp assembly  118  of  FIG. 2 . Two legs  228  of each U-bolt  220  are received by and fastened to the clamping plate  222 , and the axle housing  110  is mounted between the two sets of legs. To prevent the relative rotation of the axle housing  110  to the clamp assembly  216 , the legs  228  of the U-bolt  220  are generally linear and abut the planar fore side  132  and the planar aft side  134  of the axle housing. 
     The top surface  144  of the axle housing  110  is rounded to approximate the curvature of the U-bolt  220 , and is received in the curved portion  236  of the U-bolts. Similar to the embodiment of  FIG. 2 , the outer radius of the top surface  144  and the bottom surface  146  is generally the same or slightly smaller than the inner radius of the curved portion  236  of the U-bolt  220  such that the axle housing mates flushly with or is cradled by the curved portion of the U-bolt. 
     The bottom surface  146  of the axle housing  110  is received in an axle saddle  226 . The axle saddle  226  has a generally flat side  240  to abut the top surface  254  of the arm  256  of the air spring assembly  216 . Opposite the generally flat side  240 , the axle saddle  226  has a generally curved side  242  to approximate the curvature of the bottom surface  146  of the axle housing  110 . 
     On a bottom surface  258  of the arm  256 , the clamping plate  222  receives the legs  228  of the U-bolts  220 . Fasteners can be used to secure the legs  228  to the clamping plate  222 . It contemplated that the clamping plate  222  can have any shape that corresponds to the bottom surface  258  of the arm  256 .