Abstract:
The inventive fabricated steer axle assembly includes an axle beam, a kingpin housing, and, a fabrication connecting the axle beam and kingpin housing. The kingpin housing comprises an open-ended cylindrical tube having a groove disposed proximate each end of the tube. The fabrication includes a first end and a second end and is bent around the kingpin housing so that the first and second ends may be attached to the axle beam. A continuous weld may be used to couple the ends of the fabrication to the axle beam and secure the ends of the fabrication together along a seam extending between the kingpin housing and the beam formed after bending the fabrication around the kingpin housing.

Description:
BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     This invention relates to a steer axle assembly and more particularly to a fabricated steer axle assembly designed to reduce the amount of required welding, materials and weight and to allow flexibility with respect to the drop of the axle. 
     2. Disclosure of Related Art 
     In a conventional steer axle assembly, an I-shaped or tubular beam extends along a longitudinal axis. Each end of the beam may define a boss having a through bore configured to receive a kingpin. A steering knuckle may be rotatably mounted on the kingpin. Variations in the drop of the axle (i.e., the variation in position of the steering knuckle and vehicle wheels relative to the longitudinal axis of the axle beam) are accomplished either by curving each end of the beam or by affixing a plurality of plates or other structural components to each end of the beam so that the boss is disposed on one side of the longitudinal axis of the beam. Most conventional steer axle assemblies are forged. A steer axle assembly may also be fabricated, however. A typical fabricated steer axle assembly is welded together from numerous pieces and/or contains numerous welds for reinforcement. 
     Conventional forged and fabricated steer axle assemblies suffer from several disadvantages. Forged steer axle assemblies are relatively heavy and inflexible with respect to design changes. Further, the extra material required for forging increases tooling, manufacturing, and assembly costs. Fabricated steer axle assemblies overcome some of the above-mentioned disadvantages associated with forged steer axle assemblies. Conventional fabricated steer axle assemblies, however, include numerous pieces and welds. The relatively large number of pieces and welds increases the costs of the assembly while decreasing the overall strength of the assembly. 
     There is thus a need for a steer axle assembly that will minimize or eliminate one or more of the above-mentioned deficiencies. 
     SUMMARY OF THE INVENTION 
     This invention relates to a steer axle assembly. 
     A steer axle assembly in accordance with the present invention includes an axle beam, a kingpin housing, and a fabrication connecting the axle beam and kingpin housing. The kingpin housing may comprise a tube having a groove proximate each end of the tube. The grooves may extend around the entire circumference of the tube. The fabrication includes a first end and a second end and is bent around the kingpin housing so that the first and second ends may be attached to the axle beam. The fabrication may then be welded along the seam extending between the kingpin housing and the beam formed after bending the fabrication around the kingpin housing. 
     A steer axle assembly in accordance with the present invention is advantageous as compared to conventional steer axle assemblies. The inventive assembly is lighter than a conventional forged assembly, requires less material to manufacture, and allows flexibility in the drop of the axle. The inventive assembly also has relatively few components and welds thereby producing a relatively strong assembly at a relatively low cost. 
     These and other features and objects of this invention will become apparent to one skilled in the art from the following detailed description and the accompanying drawings illustrating features of this invention by way of example. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     FIG. 1 is a perspective view of a steer able assembly in accordance with the present invention. 
     FIG. 2 is a cross-sectional view of the steer axle assembly of FIG.  1 . 
     FIGS. 3-4 are perspective and top view illustrating steps in a method of manufacturing a steer axle assembly in accordance with the present invention. 
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
     Referring now to the drawings wherein like reference numerals are used to identify identical components in the various views, FIGS. 1-2 illustrate a steer axle assembly  10  in accordance with the present invention. Assembly  10  is provided for use in a vehicle to support the components of a pair of wheel assemblies disposed on opposite sides of the vehicle including, for example, steering knuckles (not shown) and wheel hubs (not shown). Assembly  10  is particularly adapted for use in large trucks. It should be understood, however, that the present invention may find application in a wide variety of vehicles. Assembly  10  includes an axle beam  12 , a kingpin housing  14 , and a fabrication  16 . In the illustrated embodiment, only one end of the axle assembly  10  is illustrated. It should be understood, however, that the other end of assembly  10  may be similarly constructed. In particular, the other end of beam  12  may include a similar housing  14  and fabrication  16 . 
     Beam  12  is provided to support a vehicle frame (not shown) on wheels (not shown) disposed proximate either end of beam  12 . Beam  12  may be made from conventional metals and metal alloys such as steel and may be forged or fabricated. Beam  12  may extend along a longitudinal axis  18 . Beam  12  may be tubular, as shown, and may be shaped so as to have a generally rectangular cross-section in planes extending perpendicular to axis  18 . It should be understood by those of skill in the art, however, that the cross-sectional shape of beam  12  may be varied and that beam  12  may have cross-sections of varying shape in planes perpendicular to axis  18  without departing from the spirit of the present invention. 
     Kingpin housing  14  is provided to receive a kingpin (not shown) on which a steering knuckle (not shown) may be mounted to allow rotation of the vehicle wheels (not shown). Housing  14  may be made from steel or other conventional metals or metal alloys. Housing  14  may comprise a generally cylindrical tube that is open at both ends  20 ,  22  and may include grooves  24 ,  26  (best shown in FIG. 3) proximate each end  20 ,  22 . Grooves  24 ,  26  may extend around the entire circumference of housing and are provided to receive a portion of fabrication  16  in order to secure housing  14  against movement within fabrication  16 . 
     Fabrication  16  is provided to couple beam  12  and housing  14  and to allow variation in the drop of the axle. Fabrication  16  may also be made from steel or other conventional metals or metal alloys. Referring to FIG. 3, fabrication  16  is illustrated prior to assembly within assembly  10 . Fabrication  16  may be made through a conventional blanking process and may be unitary in construction and symmetrical in shape. Prior to assembly, fabrication  16  includes top, bottom, and side walls  28 ,  30 ,  32 , respectively, defining a C-shaped channel. Top and bottom walls  28 ,  30  define notches  34 ,  36  configured to receive kingpin housing  14  upon assembly. Fabrication  16  has a first end  38  and a second end  40  each of which may be coupled to beam  12  through welding or in other ways conventional in the art. Referring again to FIGS. 1 and 2, fabrication  16  may be coupled to an external surface of beam  12  and may be disposed on one side of longitudinal axis  18 . In the illustrated embodiment, at least a portion of fabrication  16  curves toward axis  18  as fabrication  16  extends in an outboard direction from beam  12 . It should be understood that the length, shape, and configuration of fabrication  16  may be varied in order to vary the drop of the axle. The length, shape, and configuration of fabrication  16  may be adjusted using any of a variety of conventional forming methods either before capture of housing  14  or after capture of housing  14  within fabrication  16  and prior to coupling of fabrication  16  to beam  12 . 
     Referring now to FIGS. 3-4, a method of manufacturing a steer axle assembly in accordance with the present invention will be described. The method may first include the step of providing beam  12 , housing  14 , and fabrication  16 . Prior to assembly, fabrication  16  may appear as illustrated in FIG.  3 . However, the shape and configuration of fabrication  16  may be varied without departing from the spirit of the present invention. 
     The method of manufacture may also include the step of shaping fabrication  16  in order to couple beam  12  and housing  14  and form assembly  10 . Referring to FIGS. 3-4, this step may include the substep of bending fabrication  16  around housing  14  so that ends  38 ,  40  of fabrication  16  are adjacent to one another and may be coupled to beam  12 . During this substep, the portions of walls  28 ,  30  of fabrication  16  that define notches  34 ,  36  are received within grooves  24 ,  26  of housing  14  so that housing  14  is secured against movement within fabrication  16 . 
     The method of manufacture may further include the step of coupling fabrication  16  to beam  12  as illustrated in FIGS. 1-2 and  4 . Ends  38 ,  40  of fabrication  16  may be coupled to beam  12  by welding or in other ways conventional in the art. The method of manufacturing assembly  10  may also include the step of welding a pair of seams  42  (only one of which is shown in FIG. 1) formed in fabrication  16  and extending between kingpin housing  14  and beam  12  after bending fabrication  16  around housing  14 . The seams  42  are defined by the edges of top and bottom walls  28 ,  30 . In accordance with the present invention, assembly  10  reduces the number of welds required to fashion assembly  10 . In particular, a single continuous weld may be used to weld housing  14  to fabrication  16 , weld seams  42  of fabrication  16  and couple ends  38 ,  40  of fabrication  16  to beam  12 . 
     In addition to the above-described steps, the method of manufacturing assembly  10  may also include the step of adjusting the length, shape, or configuration of fabrication  16  prior to welding ends  38 ,  40  to beam  12  or welding seams  42  so as to allow variation in the drop of the axle. In this manner, the present invention allows relatively easy variation in the axle drop as compared to many conventional steer axle assemblies in which additional plates and welds are required. 
     A steer axle assembly  10  in accordance with the present invention represents a significant improvement as compared to conventional steer axle assemblies. In particular, assembly  10  weighs less and requires less material than forged steer axle assemblies. Moreover, the inventive assembly  10  allows relatively easy variation in the drop of the axle either through adjusting the length of fabrication  16  during assembly or through construction of fabrications of varying lengths, shapes, and configurations. As compared to conventional fabricated steer axle assemblies, the inventive assembly  10  requires relatively few components and welds. In particular, fabrication  16  is formed from a single piece and may be coupled to beam  12  and housing  14  using a single continuous weld. As a result, the inventive assembly is easier to build and stronger than conventional fabricated assemblies. 
     While the invention has been particularly shown and described with reference to the preferred embodiments thereof, it is well understood by those skilled in the art that various changes and modifications can be made in the invention without departing from the spirit and scope of the invention.