Patent Publication Number: US-11648745-B2

Title: Modular tooling for axle housing and manufacturing process

Description:
FIELD 
     The disclosure relates to axle assemblies for vehicles, such as front or rear drive axle assemblies used in automobiles and trucks. 
     BACKGROUND 
     This section provides background information related to the present disclosure which is not necessarily prior art. 
     Axle assemblies are commonly used to support and/or rotationally drive the wheels of a vehicle. For example, a vehicle may include a front axle assembly to which front wheels of the vehicle are mounted and a rear axle assembly to which rear wheels of the vehicle are mounted. Typically, the front and rear axle assemblies extend across the vehicle in a transverse direction that is perpendicular to the direction of vehicle travel. The front and rear axle assemblies support the front and rear wheels and are connected to a body and/or frame of the vehicle by front and rear suspension systems that articulate to allow the front and rear axle assemblies to move up and down relative to the body and/or frame of the vehicle. 
     One or more axle assemblies of the vehicle may also transfer rotational power and torque provided by an engine of the vehicle to the wheels. For example, the engine may rotationally drive a drive shaft through a transmission assembly. The axle assembly may include a carrier assembly having a pinion gear that is rotationally driven by the drive shaft in meshed engagement with a ring gear. The ring gear is fixed for rotation with a differential that transfers rotational power and torque from the pinion gear to a pair of axle shafts that extend out from the differential in opposite transverse directions. The carrier assembly includes a pinion input bearing used to support the pinion gear. The axle assembly includes an axle housing typically comprising an upper housing half welded to a lower housing half. The carrier assembly is at least partially disposed within the axle housing and fixed thereto. 
     To meet customer demand, manufacturers provide several different vehicle designs for particular uses. The various axle assemblies exhibit different dimensional characteristics. A major driving factor of the size of the axle housing is its torque transfer capacity. Elements such as a differential housing, differential bearings, and a ring gear are positioned within the axle housing. An open cavity within the axle housing must be appropriately sized. The type of suspension implemented as well as the vehicle track drives the dimensions associated with the elongated and transversely extending portions of the axle assembly. 
     Today, manufacturing facilities are often equipped with many different presses and sets of stamping/forming dies required to manufacture the plethora of available axle assemblies. The cost of individual die sets and presses is extremely high. A need in the art exists for axle assembly tooling that is easily convertible to produce several different final axle assembly product configurations using a common press and modular tooling. 
     SUMMARY 
     This section provides a general summary of the disclosure, and is not a comprehensive disclosure of its full scope or all of its features. 
     A modular tooling die for an axle housing of a vehicle comprises a post assembly including a plurality of separable post segments positioned adjacent to one another. The post assembly adapted to support a first u-shaped workpiece. A pad assembly is linearly moveable along the first axis for clamping the workpiece to the post. The pad assembly includes a plurality of separable pad segments positioned adjacent to one another. A cam driver assembly is moveable along the first axis and includes a plurality of separable cam driver segments positioned adjacent to one another. A first cam slide assembly is linearly moveable along a second axis that extends perpendicularly to the first axis. A second cam slide assembly is linearly moveable along the second axis in a direction opposite the first cam slide assembly. Each cam driver segment includes a first cam surface and an opposing second cam surface. The first cam surface extends at an angle relative to the first axis outwardly away from the post assembly. The second cam surface extends at an angle relative to the first axis outwardly away from the post assembly. The first cam slide assembly includes separable first cam slide segments. Each first cam slide segment corresponds to one of the cam driver segments and includes a third cam surface facing a corresponding first cam surface, the second cam slide assembly includes separable second cam slide segments. Each second cam slide segment corresponds to one of the cam driver segments and includes a fourth cam surface facing a corresponding second cam surface. The first cam surfaces engage the third cam surfaces and the second cam surfaces engage the fourth cam surfaces to move the first cam slide assembly and the second cam slide assembly toward the post assembly when the cam driver assembly moves toward the first and second cam slides. The first cam assembly and the second cam assembly are configured to shear portions of the first workpiece as they translate toward one another. Each of the post segments, cam driver segments, first cam slide segments, and second cam slide segments that correspond to one another by being coaxially aligned along the first axis are grouped together as die sets. Any one or more of the die sets are replaceable by another die set to account for a second workpiece having different geometry than the first workpiece. 
     A method of manufacturing an axle housing using a modular tooling die comprises providing first, second and third die sets, determining that the first and second die sets are to be employed for forming a first geometrically predefined shell, placing the first and second die sets in a forming press, positioning the third die set outside of the forming press, positioning a first rectangular metal blank in the forming press, and engaging the first and second die sets with the first metal blank to define the geometrically predefined shell. When a differently shaped or sized axle housing is to be manufactured, the method and modular tooling continues by determining that the first and third die sets are to be employed for forming a second geometrically predefined shell, replacing the second die set with the third die set in the forming press, positioning the second die set outside of the forming press, positioning a second rectangular metal blank in the forming press, and engaging the first and third die sets with the second metal blank to define the second geometrically predefined shell. 
    
    
     
       DRAWINGS 
       Other advantages of the present invention will be readily appreciated, as the same becomes better understood by reference to the following detailed description when considered in connection with the accompanying drawings wherein: 
         FIG.  1    is a front perspective view of an exemplary axle assembly that has been constructed in accordance with the present disclosure and that is shown in combination with an exemplary suspension system; 
         FIG.  2 A  is a front perspective view of the exemplary axle assembly shown in  FIG.  1   ; 
         FIG.  2 B  is a front perspective view of another exemplary axle assembly; 
         FIG.  2 C  is a front perspective view of another exemplary axle assembly; 
         FIG.  3    is an exploded perspective view of the exemplary axle assembly shown in  FIG.  1   ; 
         FIG.  4    is an exploded perspective view of a carrier assembly of the exemplary axle assembly shown in  FIG.  1   ; 
         FIG.  5 A  is a perspective view of a rectangularly shaped metal blank; 
         FIG.  5 B  is a perspective view of a metal shell having completed the forming process; 
         FIG.  5 C  is a perspective view depicting an upper beam and scrap portions separated from the upper beam by a trimming process; 
         FIG.  6    is a perspective view depicting a forming die for defining the geometry of the shell depicted in  FIG.  5 B ; 
         FIG.  7    is an exploded perspective view of the forming die of  FIG.  6   ; 
         FIG.  8    is a perspective view of a trim die operable to remove the scrap portions from the shell as illustrated in  5 C; 
         FIG.  9    is an exploded perspective view of the trim die; 
         FIG.  10    is an exploded perspective view of a portion of the trim die; and 
         FIG.  11    is a cross-sectional view of the trim die depicting a trimming operation. 
     
    
    
     DETAILED DESCRIPTION 
     Referring to the Figures, wherein like numerals indicate corresponding parts throughout the several views, an axle assembly  20  for a vehicle is illustrated. 
     Example embodiments are provided so that this disclosure will be thorough, and will fully convey the scope to those who are skilled in the art. Numerous specific details are set forth such as examples of specific components, devices, and methods, to provide a thorough understanding of embodiments of the present disclosure. It will be apparent to those skilled in the art that specific details need not be employed, that example embodiments may be embodied in many different forms and that neither should be construed to limit the scope of the disclosure. In some example embodiments, well-known processes, well-known device structures, and well-known technologies are not described in detail. 
     The terminology used herein is for the purpose of describing particular example embodiments only and is not intended to be limiting. As used herein, the singular forms “a,” “an,” and “the” may be intended to include the plural forms as well, unless the context clearly indicates otherwise. The terms “comprises,” “comprising,” “including,” and “having,” are inclusive and therefore specify the presence of stated features, integers, steps, operations, elements, and/or components, but do not preclude the presence or addition of one or more other features, integers, steps, operations, elements, components, and/or groups thereof. The method steps, processes, and operations described herein are not to be construed as necessarily requiring their performance in the particular order discussed or illustrated, unless specifically identified as an order of performance. It is also to be understood that additional or alternative steps may be employed. 
     When an element or layer is referred to as being “on,” “engaged to,” “connected to,” or “coupled to” another element or layer, it may be directly on, engaged, connected or coupled to the other element or layer, or intervening elements or layers may be present. In contrast, when an element is referred to as being “directly on,” “directly engaged to,” “directly connected to,” or “directly coupled to” another element or layer, there may be no intervening elements or layers present. Other words used to describe the relationship between elements should be interpreted in a like fashion (e.g., “between” versus “directly between,” “adjacent” versus “directly adjacent,” etc.). As used herein, the term “and/or” includes any and all combinations of one or more of the associated listed items. 
     Although the terms first, second, third, etc. may be used herein to describe various elements, components, regions, layers and/or sections, these elements, components, regions, layers and/or sections should not be limited by these terms. These terms may be only used to distinguish one element, component, region, layer or section from another region, layer or section. Terms such as “first,” “second,” and other numerical terms when used herein do not imply a sequence or order unless clearly indicated by the context. Thus, a first element, component, region, layer or section discussed below could be termed a second element, component, region, layer or section without departing from the teachings of the example embodiments. 
     Spatially relative terms, such as “inner,” “outer,” “beneath,” “below,” “lower,” “above,” “upper,” and the like, may be used herein for ease of description to describe one element or feature&#39;s relationship to another element(s) or feature(s) as illustrated in the figures. Spatially relative terms may be intended to encompass different orientations of the device in use or operation in addition to the orientation depicted in the figures. For example, if the device in the FIGS. is turned over, elements described as “below” or “beneath” other elements or features would then be oriented “above” the other elements or features. Thus, the example term “below” can encompass both an orientation of above and below. The device may be otherwise oriented (rotated 90 degrees or at other orientations) and the spatially relative descriptors used herein interpreted accordingly. 
       FIG.  1    illustrates the axle assembly  20  of the present disclosure connected to an exemplary suspension system  22 . The axle assembly  20  includes an axle housing  24  and a carrier assembly  26 . The axle housing  24  extends longitudinally along a longitudinal axis  28  between a first wheel end  30  and a second wheel end  32 . The axle housing  24  includes a center section  34 , a first tubular segment  36  that extends longitudinally between the first wheel end  30  and the center section  34 , and a second tubular segment  38  that extends longitudinally between the second wheel end  32  and the center section  34 . The carrier assembly  26  includes a carrier housing  40  and a self-lubricating cartridge pinion input bearing  42  that is mounted to the carrier housing  40 . A first self-lubricating and unitized grease wheel end bearing  44  is mounted to the first wheel end  30  of the axle housing  24  and a second self-lubricating and unitized grease wheel end bearing  46  is mounted to the second wheel end  32  of the axle housing  24 . Each of the first and second self-lubricating and unitized grease wheel end bearings  44 ,  46  include wheel flanges  48  that are provided with circumferentially spaced wheel studs  50 . A brake rotor  52  may be mounted to the wheel flanges  48  with the wheel studs  50  extending through the brake rotor  52 . It should therefore be appreciated that the wheels of a vehicle (not shown) may be secured to the wheel flanges  48  of the first and second self-lubricating and unitized grease wheel end bearings  44 ,  46  by the wheel studs  50 . 
     The suspension system  22  supporting the axle assembly  20  includes a pair of leaf springs  54  and a pair of dampers  56 . Both the leaf springs  54  and the dampers  56  are connected to the axle assembly  20  by a pair of shackles  58 . The shackles  58  include shackle plates  60  that are clamped to the first and second tubular segments  36 ,  38  of the axle housing  24  by U-bolts  62 . The free ends of the leaf springs  54  and dampers  56  shown in  FIG.  1    are configured to bolt to a body or frame of the vehicle (not shown). It should be appreciated that the axle assembly  20  illustrated in  FIG.  1    could serve as either a front axle or rear axle of the vehicle. 
     Referring now to  FIGS.  2 A,  3  and  4   , the center section  34  of the axle housing  24  is hollow, as are the first and second tubular segments  36 ,  38 . The center section  34  and the first and second tubular segments  36 ,  38  of the axle housing  24  therefore cooperate to define a combined inner volume  64  of the axle housing  24 . The axle housing  24  includes an upper beam  66  and a lower beam  68  that are positioned in a clam-shell arrangement. As a result, the upper and lower beams  66 ,  68  cooperate to form the center section  34  and the first and second tubular segments  36 ,  38  of the axle housing  24 . The upper beam  66  of the axle housing  24  includes an upper wall  70  and a pair of upper beam side walls  72  that extend down from the upper wall  70 . The lower beam  68  of the axle housing  24  includes a lower wall  74  and a pair of lower beam side walls  76  that extend up from the lower wall  74 . Consequently, the upper and lower beams  66 ,  68  having opposing U-shaped cross-sections when viewed from the side (i.e., the cross-sections of the upper and lower beams  66 ,  68  are U-shaped when the cross-sections are taken along a transverse plane  78  that is perpendicular to the longitudinal axis  28 ). 
     The upper beam  66  of the axle housing  24  includes a first longitudinal section  80 , a second longitudinal section  82 , and an upwardly curved section  84  positioned longitudinally between the first and second longitudinal sections  80 ,  82 . The lower beam  68  of the axle housing  24  includes a third longitudinal section  86 , a fourth longitudinal section  88 , and a downwardly curved section  90  that is positioned longitudinally between the third and fourth longitudinal sections  86 ,  88 . The first longitudinal section  80  of the upper beam  66  cooperates with the third longitudinal section  86  of the lower beam  68  to form the first tubular segment  36  of the axle housing  24 . The second longitudinal section  82  of the upper beam  66  cooperates with the fourth longitudinal section  88  of the lower beam  68  to form the second tubular segment  38  of the axle housing  24 . The upwardly curved section  84  of the upper beam  66  and the downwardly curved section  90  of the lower beam  68  thus form the center section  34  of the axle housing  24 . Although other configurations are possible, the upper and lower beams  66 ,  68  may be made of metal, such as iron, steel, or aluminum, and the upper beam side walls  72  may be welded to the lower beam side walls  76  at first and second seams  92 ,  94 , which are disposed on opposing sides of the center section  34 . Truss plates  96  may also be welded to the upper and lower beam side walls  70 ,  76  near the center section  34  for added strength and/or ease of manufacturing. A mounting ring  97  is fixed to axle housing  24  by a continuous weld. Threaded mounting holes  99  are circumferentially spaced apart to facilitate coupling carrier assembly  26  to axle housing  24 . Optionally, the first and second tubular segments  36 ,  38  of the axle housing  24  have an inward taper  98  at the first and second wheel ends  30 ,  32  to accommodate the first and second self-lubricating and unitized grease wheel end bearings  44 ,  46 . 
     The carrier assembly  26  is housed in the center section  34  of the axle housing  24  and the carrier housing  40  is fixedly mounted to the center section  34  of the axle housing  24 . A differential cover plate  100  is also fixedly mounted to the center section  34  of the axle housing  24 , opposite the carrier housing  40 . Although other configurations are possible, both the carrier housing  40  and the differential cover plate  100  may be made of metal, such as iron, steel, or aluminum, and may be bolted or welded to the axle housing  24 . The carrier assembly  26  also includes a pinion  102  and a differential assembly  104 . 
     The pinion  102  includes a pinion gear  106  and a pinion shaft  108  that extends through the carrier housing  40  along a pinion shaft axis  110 . The pinion shaft axis  110  extends perpendicularly relative to the longitudinal axis  28  of the axle housing  24  and is spaced from the longitudinal axis  28  by a hypoid offset distance  112  (see  FIG.  5   ). By way of example only and without limitation, the hypoid offset distance  112  may be small, such as 1 to 20 millimeters (mm) and preferably 10 millimeters (mm). This small hypoid offset reduces friction (e.g., scuffing losses) in the pinion gear mesh by approximately 3 percent compared to larger hypoid offset distances in the 35-45 millimeter (mm) range. 
     If the hypoid offset is reduced to zero, the axes would intersect and the gear arrangement would no longer be considered a hypoid gearset but be labeled as a spiral bevel gearset. For many applications, it is important that at least some hypoid offset is provided to allow the gearset to transmit a higher torque than a similarly sized spiral bevel gearset. The hypoid arrangement also introduces some relative sliding motion across the contact pattern between the pinion gear and the ring gear which produces a quiet gearset during operation. The embodiment of the present disclosure provides an optimized final drive gearset by simultaneously minimizing the hypoid offset to increase mechanical efficiency of the gearset while maintaining a desired amount of hypoid offset to increase torque transfer capacity and reduce noise. 
     It should be appreciated that the hypoid offset reduction is made possible by implementing a combination of features. The carrier housing  40  is stiffened by integrally forming the carrier housing with a number of particularly sized and positioned ribs to maintain proper position of pinion gear  106 . In addition, the loading configuration of the pinion shaft is changed from the typical cantilevered arrangement where both pinion shaft bearings are on one side of the pinion gear to a straddled design where the cartridge bearing is on one side of the pinion gear and a spigot bearing is on the opposite side of the pinion gear. The straddled bearing design in combination with the reinforced carrier housing substantially minimizes the angular deflection imparted on the pinion shaft during torque transmission. The straddled design is described in greater detail below in relation to a spigot bearing and the improved carrier housing is described and depicted at  FIGS.  6 - 10   . 
     Pinion shaft  108  may be configured to include an inboard, or first pinion shaft segment  114  and an outboard, or second pinion shaft segment  116 . The pinion gear  106  is positioned axially between the inboard pinion shaft segment  114  and the outboard pinion shaft segment  116  such that the inboard pinion shaft segment  114  protrudes inwardly from the pinion gear  106  and the outboard pinion shaft segment  116  protrudes outwardly from the pinion gear  106  along the pinion shaft axis  110 . Pinion shaft  108  includes an eternally splined portion  117 . 
     As shown in  FIG.  4   , differential assembly  104  is rotatably supported on the carrier housing  40  by a pair of differential bearings  118 . As a result, the differential assembly  104  is rotatable relative to the carrier housing  40  about the longitudinal axis  28 . The differential bearings  118  are held between a pair of mounting bosses  120   a ,  120   b  that extend from an inboard side  122  of the carrier housing  40  and a pair of caps  124  that extend partially about the differential bearings  118 . Although other configurations are possible, the caps  124  may be bolted to the mounting bosses  120   a ,  120   b  of the carrier housing  40  via threaded fasteners  125 . Bearing adjustment nuts  127  are rotatable to vary the preload on differential bearings  118 . Retainers  129  restrict the adjustment nuts  127  from rotation after the differential bearing preload has been set. 
     Differential assembly  104  includes a differential body or differential housing  126  and a planetary gearset  128 . Planetary gearset  128  includes pinion gears  128   a  drivingly engaged with side gears  128   b . Pinions gears  128   a  are supported for rotation on a cross-shaft  131 . Alternate arrangement differential gearsets, such as parallel axis gears, are contemplated as the gearset shown is merely exemplary. 
     A ring gear  130  is fixed to the differential housing  126  and arranged in meshing engagement with the pinion gear  106 . The ring gear  130  rotates co-axially about the longitudinal axis  28  of the axle housing  24 . By way of example and without limitation, the ring gear  130  may be fixed to the differential housing  126  by laser welding instead of by a flanged and bolted connection, which can help reduce weight, eliminate fastener costs, eliminate bolts as a potential failure mode, and reduce churning losses. It should be appreciated that the differential assembly  104  may be any one of the various types of differentials known in the industry, including without limitation, open differentials, limited slip differentials, electronic differentials, and locking differentials. 
     The axle assembly  20  also includes first and second axle shafts  132 ,  134  that extend out along the longitudinal axis  28  from opposing sides of the differential assembly  104 . The first axle shaft  132  extends longitudinally through the first tubular segment  36  of the axle housing  24  between a first axle shaft inboard end  136  and a first axle shaft outboard end  138 . The second axle shaft  134  extends longitudinally through the second tubular segment  38  of the axle housing  24  between a second axle shaft inboard end  140  and a second axle shaft outboard end  142 . The first and second axle shaft inboard ends  136 ,  140  and the first and second axle shaft outboard ends  138 ,  142  are splined. The first and second axle shaft outboard ends  138 ,  142  may also include threaded portions  144 . The first and second axle shaft inboard ends  136 ,  140  are received in the differential assembly  104  and are rotationally coupled to the pinion gear  106  through the planetary gearset  128 . 
     The axle assembly  20  of the present disclosure uniquely includes a self-lubricating bearing arrangement that includes the combination of a self-lubricating cartridge pinion input bearing  42  with first and second self-lubricating and unitized grease wheel end bearings  44 ,  46 . In accordance with this arrangement, the outboard pinion shaft segment  116  is rotatably supported by the self-lubricating cartridge pinion input bearing  42 , which is mounted to the carrier housing  40  and allows the pinion  102  to rotate relative to the carrier housing  40  about the pinion shaft axis  110 . The first axle shaft outboard end  138  is rotatably supported by the first self-lubricating and unitized grease wheel end bearing  44 , which is mounted to the first wheel end  30  of the axle housing  24 . The second axle shaft outboard end  142  is rotatably supported by a second self-lubricating and unitized grease wheel end bearing  46 , which is mounted to the second wheel end  32  of the axle housing  24 . As a result, the first and second axle shafts  132 ,  134  can rotate within the axle housing  24  about the longitudinal axis  28 . 
     As explained above, wheel flanges  48  of the first and second self-lubricating and unitized grease wheel end bearings  44 ,  46  have circumferentially spaced wheel studs  50 . Wheel flanges  48  are connected to and rotate with an inner race  146  of the first and second self-lubricating and unitized grease wheel end bearings  44 ,  46 . The inner races  146  include splined bores  148  that receive the first and second axle shaft outboard ends  138 ,  142  such that the splines on these respective components rotatably couple the inner races  146  and thus the wheel flanges  48  to the first and second axle shafts  132 ,  134 . Because the splines on the first and second axle shaft inboard ends  136 ,  140  mate with the differential assembly  104 , which is rotatably driven by the ring gear/pinion gear mesh, the rotational power and torque of the engine can be transmitted to the wheels of the vehicle. The first and second self-lubricating and unitized grease wheel end bearings  44 ,  46 , also include outer races  147  that extend annularly about the inner races  146 . The outer races  147  are fixedly mounted to the first and second wheel ends  30 ,  32  of the axle housing  24 , such as by welding or a bolted connection. Greased bearings (not shown) may be provided between the inner and outer races  146 ,  147  to reduce friction. These greased bearings could be tapered roller bearings, high contact ball bearings, or a combination of tapered roller bearings and high contact ball bearings depending on the desired load rating. Wheel end nuts  150  thread onto the threaded portions  144  of the first and second axle shaft outboard ends  138 ,  142  to prevent free play along the longitudinal axis  28  between the wheel flanges  48  and the first and second axle shafts  132 ,  134 . 
     In accordance with this design, the first and second axle shafts  132 ,  134  are provided in a full floating arrangement, where both the first and second axle shaft inboard ends  136 ,  140  and both the first and second axle shaft outboard ends  138 ,  142  have splined connections and are supported by bearings  44 ,  46 ,  118 . This full floating arrangement provides better support for the first and second axle shafts  132 ,  134 , which reduces binding and distributes loading between multiple bearings  44 ,  46 ,  118  for improvements in mechanical efficiency and durability. 
     With reference to  FIGS.  2 A,  2 B and  2 C , three different exemplary axle assemblies  20 ,  20 B and  20 C are illustrated. As previously described, axle assembly  20  includes first longitudinal section  80  having a length LA, second longitudinal section  82  having a length RA and upperwardly curved section  84  coupled to downwardly curved section  90  that in combination define a diameter DA. In the embodiment depicted in the  FIG.  2 A  length LA is substantially the same as RA but this is not necessarily the case in all instances. For example, axle assembly  20 B includes a longitudinal section length LB substantially less than the opposing leg length RB.  FIG.  2 B  depicts an axle having an increased torque transfer rating as compared to the axle depicted in  FIG.  2 A . As such, the carrier assembly and the associated axle housing center section diameter DB is greater than DA. In yet another arrangement, axle assembly  20 C effectively includes only upperwardly curved section  84 C fixed to downwardly curved section  90 C. The length of the first and second longitudinal sections are effectively zero or a relatively short distance. 
       FIGS.  5 A,  5 B and  5 C  depict work-in-process stages associated with manufacturing steps of the present disclosure to form upper beam  66  in a final configuration prior to welding to lower beam  68 .  FIG.  5 A  depicts a rectangular plate  156  having parallel edges  158 ,  160  that define a width as well as parallel interfaces  162 ,  164  that define a length of plate  156 . Parallel opposite surfaces  166 ,  168  define a thickness of plate  156 . It should be appreciated that plate  156  may be provided by simply de-coiling a portion of a metal roll and cutting one of the edges to define a length or a width of the plate  156 . 
       FIG.  5 B  depicts a formed shell  170  that has been shaped by a forming die  180  shown in  FIGS.  6  and  7   . Forming die  180  performs a stamping operation to impart complex shapes to previously planar plate  156 . Shell  170  includes a majority of the features of upper beam  66  including first longitudinal section  80 , second longitudinal section  82 , upwardly curved section  84  and inward taper  98 . Shell  170  includes excess material along the edges of upper beam sidewalls  72  which is subsequently removed in a trim die  186  depicted  FIGS.  8 - 11   .  FIG.  5 C  illustrates the finalized upper beam  66  positioned adjacent to two pieces of scrap  188  removed from shell  170  during the trimming operation performed by trim die  186 . 
       FIGS.  7  and  8    depict a modular forming die  180  including an upper die assembly  190  and a lower die assembly  194  positioned between a ram  198  and a bed  202 . It should be appreciated that the terms “upper” and “lower” are merely used for convenience. Ram  198  need not be vertically oriented relative to ground but may be oriented in this manner to utilize gravitational forces. 
     Upper die assembly  190  includes a plurality of individual removable upper dies  206   a ,  206   b ,  206   c ,  206   d ,  206   e ,  206   f , and  206   g . Lower die assembly  194  includes a plurality of individual removable lower dies  210   a ,  210   b ,  210   c ,  210   d ,  210   e ,  210   f , and  210   g . Upper dies and lower dies with the same suffix form a pair to impart a predefined geometry on plate  156  and define an associated portion of shell  170 . During operation, ram  198  is fixed to upper die assembly  190  while lower die assembly  194  fixed to bed  202 . Upper die assembly  190  is spaced apart from lower die assembly  194  by axially translating ram  198  away from bed  202 . Plate  156  is inserted between upper die assembly  190  and lower die assembly  194  while the die assemblies are spaced apart. Ram  198  is axially translated toward bed  202  to drivingly engage upper die assembly  190  with plate  156 . As ram  198  axially translates toward bed  202 , partially formed plate  156  engages lower die assembly  194 . Upon completion of translation of ram  198 , shell  170  is completely defined. The formed shell  170  is removed after ram  198  axially translates away from bed  202  sufficient amount. 
     As previously described, several dimensional characteristics of shell  170 , including the size and shape of upwardly curved section  84 , first longitudinal section  80 , second longitudinal section  82 , and inward taper  98 , may be changed by replacing a given upper and lower die set with an alternate upper and lower die set. For example,  FIG.  6    depicts upper die  206   d  configured to cooperate with lower die  210   d  to define the size and shape of upwardly curved section  84 . Upper die assembly  190  and lower die assembly  194  may be reconfigured in a relatively simple manner if a differently shaped shell  170  is required. It is contemplated that the same ram  198  and bed  202  may be used to form differently dimensioned shells  170 . 
     If it is desirable to form a shell  170  having a differently sized carrier assembly than previously formed, the geometry of upwardly curved section  84  will also change. A replacement die set including an upper die  214   d  and a lower die  214   e , having appropriately revised dimensions, will replace upper die  206   d  and lower die  210   d . If the size and shape of the first longitudinal section  80  and second longitudinal section  82  remain the same as the previous shell, no need exists to change out pairs of dies  206   c ,  210   c  or  206   e ,  210   e . On the contrary, if the size or shape of the longitudinal sections have changed, these die sets may also be replaced. It should be appreciated that a quick-change manufacturing environment may be provided by maintaining various pairs of upper and lower forming dies to define a virtually unlimited number of axial housings. In the embodiment shown in  FIG.  6   , the length of upper die  206   c  is substantially the same as upper die  206   e . This is not always the case. To create axle assembly  20 B, as depicted in  FIG.  2 B , one of the pairs of dies would be substantially shorter than the other. 
     To minimize the number of die sets required to manufacture several different axle housings, it may be beneficial to incorporate a set of shim sets similar to upper die  206   b ,  210   b  as well as  206   f ,  210   f . If a minimum axle leg length (longitudinal section length) is known, die sets  206   c ,  210   c  and  206   e ,  210   e  may be formed at this minimum length. Axle assemblies that require longer longitudinal sections legs would be manufactured using upper die assemblies and lower die assemblies that include one or more shim sets such as  206   b ,  210   b.    
     A desired end configuration of a given axle housing may vary from square, round, or rectangularly-shaped. The end shape is defined by die sets comprising upper dies  206   a ,  210   a  and  206   g ,  210   g . Once again, these end configuration die sets are easily removable and replaced with other die sets as desired. 
     In yet another example, it may be desirable to construct an axle housing having an increased wall thickness. To change the material wall thickness of shell  170 , an increased plate  156  is supplied. Replacement die sets having increased clearance would be inserted to account for the increased plate thickness. 
     With reference to  FIGS.  8 - 11   , trim die  186  is operable to shear scrap portions  188  from shell  170  to define finalized upper beam  66 . A need exists for trim die  186  because the cutting operation to remove scrap portions  188  occurs 90° to the direction in which ram  198  of forming die  180  travels. Trim die  186  includes a cam driver assembly  252 , a spring pad assembly  256 , a first cam slide assembly  260 , a second cam slide assembly  264 , and a post assembly  268 . Cam driver assembly  252  includes separable cam driver segments  272   a ,  272   b ,  272   c ,  272   d , and  272   e  positioned adjacent to one another. Each cam driver segment is substantially similar to each other. Accordingly, only cam  272   a  will be described in detail. Cam driver segment  272   a  includes a driven surface  276   a  that is substantially planar and configured to be contacted by a ram of a press to axially translate cam driver segment  272   a  linearly along a first axis  280 . It should be appreciated that the linear translation of any one of cam driver segments  272   a - e  is deemed to move along the same direction as any similar axis extending parallel to first axis  280 . First axis  280  may be also considered to extend along a vertical direction. 
     Cam driver segment  272   a  includes a first cam surface  284   a  and an opposing second cam surface  288   a . Each of the first and second cam surfaces  284   a ,  288   a  extend at an angle relative to first axis  280  outwardly away from a post  292   a  of post assembly  268  and toward base  296   a  of post assembly  268 . It is contemplated that first cam surface  284   a  intersects first axis  280  at a 45 degree angle. Similarly, second cam surface  288   a  intersects first axis  280  at a 45 degree angle. These angles are exemplary as other angular arrangements may be implemented. 
     First cam slide assembly  260  includes a plurality of individual and separable first cam slide segments  300   a ,  300   b ,  300   c ,  300   d , and  300   e  positioned adjacent to one another. Each cam driver segment  272   a - e  includes a width as measured along a second axis  304  that extends perpendicularly to first axis  280 . Each first cam slide segment  300   a - 300   e  has a width matching the opposing and corresponding cam driver segment  272   a - 272   e . Each first cam slide segment is substantially similar to each other. Accordingly, only first cam slide segment  300   a  will be described in detail. 
     First cam slide segment  300   a  includes a third cam surface  308   a  that extends at an angle complimentary to the angle along with which second cam surface  288   a  extends. Accordingly, third cam surface  308   a  extends parallel to second cam surface  288   a . This arrangement of drive and driven surfaces causes first cam slide  300   a  to axially translate along a third axis  312  toward post  292   a  when cam driver segment  272   a  is translated along first axis  280  toward post  292   a . It should be appreciated that third axis  312  perpendicularly extends to both first axis  280  and second axis  304 . First cam slide segment  300   a  includes a bottom surface  316   a  which rests on an upper surface  320   a  of base  296   a . Relative sliding movement between the surfaces occurs during operation of trim die  186 . 
     First cam slide segment  300   a  includes a stop face  324   a  a shear support portion  328   a  and a recess  332   a . A knife  336   a  is fixed to first cam slide segment  300   a  and positioned within a rabbet  340   a  formed in shear support portion  328   a . A translatable first cam pad  344   a  is positioned within recess  332   a . First cam pad  344   a  is biased toward post  292   a  and slidable along an upper surface  348   a  of knife  336   a.    
     Second cam slide assembly  264  is configured as the mirror image of first cam slide assembly  260  and includes a plurality of individual and separable second cam slide segments  354   a ,  354   b ,  354   c ,  354   d  and  354   e  positioned adjacent to one another. Each second cam slide segment  354   a - e  has a width matching the opposing and corresponding first cam slide segment  300   a - e  as well as the corresponding cam driver segment  272   a - e . Second cam slide segment  354   a  includes a fourth cam surface  360   a  that extends at an angle complimentary to the angle which first cam surface  284   a  extends. Fourth cam surface  360   a  extends parallel to first cam surface  284   a  such that second cam slide segment  354   a  is axially driven along third axis  312  toward post  292   a  when cam driver segment  272   a  is translated along first axis  280  toward post  292   a . Second cam slide segment  354   a  includes a stop face  364   a , a shear support portion  368   a , and a recess  372   a . A knife  376   a  is fixed to second cam slide segment  354   a  and positioned within a rabbet  380   a  formed in shear support portion  368   a . A translatable second cam pad  384   a  is positioned within recess  372   a . Second cam pad  384   a  is urged toward post  292   a  by mechanism such as a spring (not shown). 
     Spring pad assembly  256  includes a plurality of individual and separable spring pad segments  396   a ,  396   b ,  367   c ,  396   d  and  396   e  positioned adjacent to one another. Each spring pad is substantially similar to each other. Only spring pad segment  396   a  will be described in detail. Spring pad segment  396   a  includes a piston  398   a  and a body  400   a  urged toward  290   a  by a spring  404   a . Body  400   a  includes an engagement surface  408   a  that is driven into contact with an upper surface of shell  170  to clamp shell  170  at desired location on post  292   a.    
       FIG.  9    depicts groups of components of trim die  186  that define replaceable die sets. As previously described with reference to forming die  180 , trim die  186  is configurable to perform trimming operations on a variety of shells having different geometry. Certain portions of shell  170  may be dimensionally the same as portions of another shell  170  while the remaining portions may have different dimensional characteristics. For example, center section  34  of a certain shell  170  may be formed to a predefined draw depth to mate with a particularly sized carrier assembly.  FIG.  9    depicts a plurality of die sets  422   a ,  422   b ,  422   c ,  422   d , and  422   e  that are replaceable as modules of tooling sized to define the final features of a particular upper beam  66 . 
       FIG.  10    depicts a replacement central die set  422   c   1  configured to trim portions of a differently sized shell  170  that accepts a differently sized carrier assembly. Elements of central die set  422   c   1  will be identified with a numeral “1” suffix. In the center section of upper beam  66 , portions of the beam side walls may extend in a three-dimensional manner. As such, the portions of die set  422   c  or  422   c   1  that engage shell  170  also exhibit a complex shape. First cam slide segment  300   c   1  and second cam slide segment  354   c   1  include stepped faces  426   c   1 ,  430   c   1 , respectively that vary in the second axis  304  direction. Accordingly, knives  434   c   1 ,  438   c   1  include three-dimensional contours with respect to first axis  280 , second axis  304  and third axis  312 . First cam pad  344   c   1  and second cam pad  384   c   1  also exhibit complex three-dimensional shapes since each of the trim die components cooperate with one another. Post  292   c   1  is defined by a three-dimensionally complex shape to support shell  170  and provide reaction surfaces during the shearing action opposite cutting surfaces  434   c   1 ,  438   c   1 . 
       FIG.  11    provides a cross-sectional view through die set  422   b . In a production manufacturing environment, trim die  186  is configured to remove portions of material from shell  170  having a particular geometrical configuration. Based on the geometry of shell  170 , an operator selects the particular die sets that are to be positioned adjacent to one another in trim die  186  based on the geometry of the shell to be processed. It is contemplated that a tool room would be equipped with several different die sets in addition to  422   a - 422   e  and  422   c   1 . Once the appropriate die sets are loaded into the press, a workpiece such as shell  170  is positioned in engagement with post assembly  268 . At this time, cam driver assembly  252  as well first cam slide assembly  260  and second cam slide assembly  264  are positioned in their retracted positions spaced apart from post assembly  268 . In contrast, it should be appreciated that  FIG.  11    depicts each of the components of die set  422   b  at their fully extended positions after the completion of the trimming operation. 
     Returning to the description of operation of trim die  186 , once the un-trimmed shell  170  is placed on top of post assembly  268 , cam driver assembly  252  and spring pad assembly  256  are linearly translated toward post assembly  268 . For ease of explanation, the elements of die set  422   b  will be described in view of  FIG.  11   . The other adjacent portions of trim die  186  act accordingly. The trimming process continues by engaging spring pad segment  396   b  with shell  170  to clamp the shell to post  292   b . Spring  404   b  urges body  400   b  away from piston  398   b  to drivingly engage body  400   b  with shell  170 . Based on the inclusion of spring  404   b , cam driver segment  272   b  may continue to move toward post  292   b  after body  400   b  engages shell  170 . 
     First cam surface  284   b  engages fourth cam surface  360   b  at substantially the same time as second cam surface  288   b  engages third cam surface  308   b . At this time, first cam slide segment  300   b  and second cam segment  354   b  are simultaneously translated toward shell  170 . Because first cam pad  344   b  and second cam pad  384   b  are coupled to their respective first and second cam slide segments  300   b ,  354   b , these elements also translate toward shell  170 . 
     As the manufacturing process continues, and end face  442   b  of first cam pad  344   b  engages one of beam sidewalls  72  and presses the sidewall against post  292   b  to straighten and properly align the sidewall. Similarly, a second end face  446   b  of second cam pad  384   b  engages an opposite beam sidewall  76  and traps the opposite side wall against post  292   b  to straighten and properly align the sidewall. At this moment of manufacturing, end faces  442   b ,  446   b  are positioned inwardly closer to post  292   b  than the cutting edge  454   b  of knife  376   b  and a cutting edge  450   b  of knife  336   b . As cam driver assembly  252  continues to translate toward post assembly  292 , springs  460 , hydraulic rams or some other devices are positioned within recesses  332   b ,  372   b  allow cutting edges  450 ,  454   b  to approach and cut through upper beam sidewalls  72  while first and second cam pads  344   b , 384   b  maintain engagement with shell  170 . As cutting edges  450   b ,  454   b  sheer through the material, scrap pieces  188  are separated from shell  170 . The process is finalized by retracting cam driver assembly  252 , first cam slide assembly  260 , spring pad assembly  256  and second cam assembly  264 . The finalized upper beam  66  and scrap pieces  188  are removed from the trim die  186  to allow trimming of a subsequently inserted shell  170 . 
     The foregoing description of the embodiments has been provided for purposes of illustration and description. It is not intended to be exhaustive or to limit the disclosure. Individual elements or features of a particular embodiment are generally not limited to that particular embodiment, but, where applicable, are interchangeable and can be used in a selected embodiment, even if not specifically shown or described. These antecedent recitations should be interpreted to cover any combination in which the inventive novelty exercises its utility. Many modifications and variations of the present invention are possible in light of the above teachings and may be practiced otherwise than as specifically described while within the scope of the appended claims.